diff --git a/ogr/ogrsf_frmts/georss/ogr_georss.h b/ogr/ogrsf_frmts/georss/ogr_georss.h
index bd370d5a809f..3d3886a893ea 100644
--- a/ogr/ogrsf_frmts/georss/ogr_georss.h
+++ b/ogr/ogrsf_frmts/georss/ogr_georss.h
@@ -38,6 +38,8 @@
 #include "ogr_expat.h"
 #endif
 
+constexpr int PARSER_BUF_SIZE = 8192;
+
 class OGRGeoRSSDataSource;
 
 typedef enum
diff --git a/ogr/ogrsf_frmts/georss/ogrgeorssdatasource.cpp b/ogr/ogrsf_frmts/georss/ogrgeorssdatasource.cpp
index 085b6b4c3adb..8d8ce12d0e15 100644
--- a/ogr/ogrsf_frmts/georss/ogrgeorssdatasource.cpp
+++ b/ogr/ogrsf_frmts/georss/ogrgeorssdatasource.cpp
@@ -216,7 +216,7 @@ void OGRGeoRSSDataSource::dataHandlerValidateCbk(const char * /* data */,
                                                  int /* nLen */)
 {
     nDataHandlerCounter++;
-    if (nDataHandlerCounter >= BUFSIZ)
+    if (nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
@@ -270,7 +270,7 @@ int OGRGeoRSSDataSource::Open(const char *pszFilename, int bUpdateIn)
     XML_SetCharacterDataHandler(oParser, ::dataHandlerValidateCbk);
     oCurrentParser = oParser;
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     unsigned int nLen = 0;
     int nCount = 0;
@@ -282,18 +282,19 @@ int OGRGeoRSSDataSource::Open(const char *pszFilename, int bUpdateIn)
     do
     {
         nDataHandlerCounter = 0;
-        nLen = static_cast<unsigned int>(VSIFReadL(aBuf, 1, sizeof(aBuf), fp));
+        nLen = static_cast<unsigned int>(
+            VSIFReadL(aBuf.data(), 1, aBuf.size(), fp));
         nDone = VSIFEofL(fp);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
-            if (nLen <= BUFSIZ - 1)
+            if (nLen <= PARSER_BUF_SIZE - 1)
                 aBuf[nLen] = 0;
             else
-                aBuf[BUFSIZ - 1] = 0;
+                aBuf[PARSER_BUF_SIZE - 1] = 0;
 
-            if (strstr(aBuf, "<?xml") &&
-                (strstr(aBuf, "<rss") || strstr(aBuf, "<feed") ||
-                 strstr(aBuf, "<atom:feed")))
+            if (strstr(aBuf.data(), "<?xml") &&
+                (strstr(aBuf.data(), "<rss") || strstr(aBuf.data(), "<feed") ||
+                 strstr(aBuf.data(), "<atom:feed")))
             {
                 CPLError(CE_Failure, CPLE_AppDefined,
                          "XML parsing of GeoRSS file failed: "
@@ -315,7 +316,7 @@ int OGRGeoRSSDataSource::Open(const char *pszFilename, int bUpdateIn)
         }
         else
         {
-            // After reading 50 * BUFSIZ bytes, and not finding whether the file
+            // After reading 50 * PARSER_BUF_SIZE bytes, and not finding whether the file
             // is GeoRSS or not, we give up and fail silently.
             nCount++;
             if (nCount == 50)
diff --git a/ogr/ogrsf_frmts/georss/ogrgeorsslayer.cpp b/ogr/ogrsf_frmts/georss/ogrgeorsslayer.cpp
index 86b1e1cfba73..60edd4197d02 100644
--- a/ogr/ogrsf_frmts/georss/ogrgeorsslayer.cpp
+++ b/ogr/ogrsf_frmts/georss/ogrgeorsslayer.cpp
@@ -977,13 +977,13 @@ OGRFeature *OGRGeoRSSLayer::GetNextFeature()
     nFeatureTabIndex = 0;
 
     int nDone = 0;
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     do
     {
         unsigned int nLen = static_cast<unsigned int>(
-            VSIFReadL(aBuf, 1, sizeof(aBuf), fpGeoRSS));
+            VSIFReadL(aBuf.data(), 1, aBuf.size(), fpGeoRSS));
         nDone = VSIFEofL(fpGeoRSS);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
             CPLError(CE_Failure, CPLE_AppDefined,
                      "XML parsing of GeoRSS file failed : %s "
@@ -1785,15 +1785,16 @@ void OGRGeoRSSLayer::LoadSchema()
     nTotalFeatureCount = 0;
     setOfFoundFields = nullptr;
 
-    char aBuf[BUFSIZ] = {};
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     do
     {
         nDataHandlerCounter = 0;
         unsigned int nLen =
-            (unsigned int)VSIFReadL(aBuf, 1, sizeof(aBuf), fpGeoRSS);
+            (unsigned int)VSIFReadL(aBuf.data(), 1, aBuf.size(), fpGeoRSS);
         nDone = VSIFEofL(fpGeoRSS);
-        if (XML_Parse(oSchemaParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oSchemaParser, aBuf.data(), nLen, nDone) ==
+            XML_STATUS_ERROR)
         {
             CPLError(
                 CE_Failure, CPLE_AppDefined,
@@ -2209,7 +2210,7 @@ void OGRGeoRSSLayer::dataHandlerLoadSchemaCbk(const char *data, int nLen)
         return;
 
     nDataHandlerCounter++;
-    if (nDataHandlerCounter >= BUFSIZ)
+    if (nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
diff --git a/ogr/ogrsf_frmts/gpx/ogr_gpx.h b/ogr/ogrsf_frmts/gpx/ogr_gpx.h
index a39f57cbf4cc..8ad24ecdd3a7 100644
--- a/ogr/ogrsf_frmts/gpx/ogr_gpx.h
+++ b/ogr/ogrsf_frmts/gpx/ogr_gpx.h
@@ -48,6 +48,8 @@ typedef enum
     GPX_TRACK_POINT,
 } GPXGeometryType;
 
+constexpr int PARSER_BUF_SIZE = 8192;
+
 /************************************************************************/
 /*                             OGRGPXLayer                              */
 /************************************************************************/
diff --git a/ogr/ogrsf_frmts/gpx/ogrgpxdatasource.cpp b/ogr/ogrsf_frmts/gpx/ogrgpxdatasource.cpp
index cd5bbaae85d9..896f7ac75167 100644
--- a/ogr/ogrsf_frmts/gpx/ogrgpxdatasource.cpp
+++ b/ogr/ogrsf_frmts/gpx/ogrgpxdatasource.cpp
@@ -443,7 +443,7 @@ void OGRGPXDataSource::dataHandlerValidateCbk(const char *data, int nLen)
     }
 
     nDataHandlerCounter++;
-    if (nDataHandlerCounter >= BUFSIZ)
+    if (nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
@@ -509,7 +509,7 @@ int OGRGPXDataSource::Open(const char *pszFilename, int bUpdateIn)
                           ::endElementValidateCbk);
     XML_SetCharacterDataHandler(oParser, ::dataHandlerValidateCbk);
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     unsigned int nLen = 0;
     int nCount = 0;
@@ -522,16 +522,17 @@ int OGRGPXDataSource::Open(const char *pszFilename, int bUpdateIn)
     do
     {
         nDataHandlerCounter = 0;
-        nLen = static_cast<unsigned int>(VSIFReadL(aBuf, 1, sizeof(aBuf), fp));
+        nLen = static_cast<unsigned int>(
+            VSIFReadL(aBuf.data(), 1, aBuf.size(), fp));
         nTotalBytesRead += nLen;
         nDone = VSIFEofL(fp);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
-            if (nLen <= BUFSIZ - 1)
+            if (nLen <= PARSER_BUF_SIZE - 1)
                 aBuf[nLen] = 0;
             else
-                aBuf[BUFSIZ - 1] = 0;
-            if (strstr(aBuf, "<?xml") && strstr(aBuf, "<gpx"))
+                aBuf[PARSER_BUF_SIZE - 1] = 0;
+            if (strstr(aBuf.data(), "<?xml") && strstr(aBuf.data(), "<gpx"))
             {
                 CPLError(CE_Failure, CPLE_AppDefined,
                          "XML parsing of GPX file failed : %s at line %d, "
@@ -559,7 +560,7 @@ int OGRGPXDataSource::Open(const char *pszFilename, int bUpdateIn)
         }
         else
         {
-            // After reading 50 * BUFSIZE bytes, and not finding whether the
+            // After reading 50 * PARSER_BUF_SIZE bytes, and not finding whether the
             // file is GPX or not, we give up and fail silently.
             nCount++;
             if (nCount == 50)
diff --git a/ogr/ogrsf_frmts/gpx/ogrgpxlayer.cpp b/ogr/ogrsf_frmts/gpx/ogrgpxlayer.cpp
index b84b9b1d81eb..abe2b784f0af 100644
--- a/ogr/ogrsf_frmts/gpx/ogrgpxlayer.cpp
+++ b/ogr/ogrsf_frmts/gpx/ogrgpxlayer.cpp
@@ -1032,7 +1032,7 @@ void OGRGPXLayer::dataHandlerCbk(const char *data, int nLen)
         return;
 
     nDataHandlerCounter++;
-    if (nDataHandlerCounter >= BUFSIZ)
+    if (nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
@@ -1102,8 +1102,7 @@ OGRFeature *OGRGPXLayer::GetNextFeature()
     if (VSIFEofL(fpGPX))
         return nullptr;
 
-    char aBuf[BUFSIZ];
-
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     CPLFree(ppoFeatureTab);
     ppoFeatureTab = nullptr;
     nFeatureTabLength = 0;
@@ -1114,10 +1113,10 @@ OGRFeature *OGRGPXLayer::GetNextFeature()
     do
     {
         nDataHandlerCounter = 0;
-        unsigned int nLen =
-            static_cast<unsigned int>(VSIFReadL(aBuf, 1, sizeof(aBuf), fpGPX));
+        unsigned int nLen = static_cast<unsigned int>(
+            VSIFReadL(aBuf.data(), 1, aBuf.size(), fpGPX));
         nDone = VSIFEofL(fpGPX);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
             CPLError(CE_Failure, CPLE_AppDefined,
                      "XML parsing of GPX file failed : "
@@ -1960,15 +1959,16 @@ void OGRGPXLayer::LoadExtensionsSchema()
     nWithoutEventCounter = 0;
     bStopParsing = false;
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     do
     {
         nDataHandlerCounter = 0;
-        unsigned int nLen =
-            static_cast<unsigned int>(VSIFReadL(aBuf, 1, sizeof(aBuf), fpGPX));
+        unsigned int nLen = static_cast<unsigned int>(
+            VSIFReadL(aBuf.data(), 1, aBuf.size(), fpGPX));
         nDone = VSIFEofL(fpGPX);
-        if (XML_Parse(oSchemaParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oSchemaParser, aBuf.data(), nLen, nDone) ==
+            XML_STATUS_ERROR)
         {
             CPLError(
                 CE_Failure, CPLE_AppDefined,
@@ -2218,7 +2218,7 @@ void OGRGPXLayer::dataHandlerLoadSchemaCbk(const char *data, int nLen)
         return;
 
     nDataHandlerCounter++;
-    if (nDataHandlerCounter >= BUFSIZ)
+    if (nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
diff --git a/ogr/ogrsf_frmts/jml/ogrjmllayer.cpp b/ogr/ogrsf_frmts/jml/ogrjmllayer.cpp
index 862047285e56..74a25d0dc855 100644
--- a/ogr/ogrsf_frmts/jml/ogrjmllayer.cpp
+++ b/ogr/ogrsf_frmts/jml/ogrjmllayer.cpp
@@ -29,6 +29,8 @@
 #include "ogr_jml.h"
 #include "ogr_p.h"
 
+constexpr int PARSER_BUF_SIZE = 8192;
+
 #ifdef HAVE_EXPAT
 
 /************************************************************************/
@@ -397,7 +399,7 @@ void OGRJMLLayer::dataHandlerCbk(const char *data, int nLen)
         return;
 
     nDataHandlerCounter++;
-    if (nDataHandlerCounter >= BUFSIZ)
+    if (nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
@@ -434,7 +436,7 @@ OGRFeature *OGRJMLLayer::GetNextFeature()
     if (VSIFEofL(fp))
         return nullptr;
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
 
     nFeatureTabLength = 0;
     nFeatureTabIndex = 0;
@@ -445,9 +447,10 @@ OGRFeature *OGRJMLLayer::GetNextFeature()
     do
     {
         nDataHandlerCounter = 0;
-        unsigned int nLen = (unsigned int)VSIFReadL(aBuf, 1, sizeof(aBuf), fp);
+        unsigned int nLen =
+            (unsigned int)VSIFReadL(aBuf.data(), 1, aBuf.size(), fp);
         nDone = VSIFEofL(fp);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
             CPLError(CE_Failure, CPLE_AppDefined,
                      "XML parsing of JML file failed : %s "
@@ -505,15 +508,15 @@ void OGRJMLLayer::LoadSchema()
 
     VSIFSeekL(fp, 0, SEEK_SET);
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     do
     {
         nDataHandlerCounter = 0;
-        const unsigned int nLen =
-            static_cast<unsigned int>(VSIFReadL(aBuf, 1, sizeof(aBuf), fp));
+        const unsigned int nLen = static_cast<unsigned int>(
+            VSIFReadL(aBuf.data(), 1, aBuf.size(), fp));
         nDone = VSIFEofL(fp);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
             CPLError(CE_Failure, CPLE_AppDefined,
                      "XML parsing of JML file failed : %s at line %d, "
diff --git a/ogr/ogrsf_frmts/kml/kml.cpp b/ogr/ogrsf_frmts/kml/kml.cpp
index af85da26bd30..aa18e88664e3 100644
--- a/ogr/ogrsf_frmts/kml/kml.cpp
+++ b/ogr/ogrsf_frmts/kml/kml.cpp
@@ -41,6 +41,8 @@
 #include "expat.h"
 #endif
 
+constexpr int PARSER_BUF_SIZE = 8192;
+
 KML::KML()
     : poTrunk_(nullptr), nNumLayers_(-1), papoLayers_(nullptr), nDepth_(0),
       validity(KML_VALIDITY_UNKNOWN), pKMLFile_(nullptr), poCurrent_(nullptr),
@@ -95,15 +97,15 @@ bool KML::parse()
 
     int nDone = 0;
     int nLen = 0;
-    char aBuf[BUFSIZ] = {0};
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     bool bError = false;
 
     do
     {
         nDataHandlerCounter = 0;
-        nLen = (int)VSIFReadL(aBuf, 1, sizeof(aBuf), pKMLFile_);
+        nLen = (int)VSIFReadL(aBuf.data(), 1, aBuf.size(), pKMLFile_);
         nDone = VSIFEofL(pKMLFile_);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
             CPLError(CE_Failure, CPLE_AppDefined,
                      "XML parsing of KML file failed : %s at line %d, "
@@ -184,23 +186,25 @@ void KML::checkValidity()
 
     int nDone = 0;
     int nLen = 0;
-    char aBuf[BUFSIZ] = {0};
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
 
     // Parses the file until we find the first element.
     do
     {
         nDataHandlerCounter = 0;
-        nLen = static_cast<int>(VSIFReadL(aBuf, 1, sizeof(aBuf), pKMLFile_));
+        nLen =
+            static_cast<int>(VSIFReadL(aBuf.data(), 1, aBuf.size(), pKMLFile_));
         nDone = VSIFEofL(pKMLFile_);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
-            if (nLen <= BUFSIZ - 1)
+            if (nLen <= PARSER_BUF_SIZE - 1)
                 aBuf[nLen] = 0;
             else
-                aBuf[BUFSIZ - 1] = 0;
-            if (strstr(aBuf, "<?xml") &&
-                (strstr(aBuf, "<kml") ||
-                 (strstr(aBuf, "<Document") && strstr(aBuf, "/kml/2."))))
+                aBuf[PARSER_BUF_SIZE - 1] = 0;
+            if (strstr(aBuf.data(), "<?xml") &&
+                (strstr(aBuf.data(), "<kml") ||
+                 (strstr(aBuf.data(), "<Document") &&
+                  strstr(aBuf.data(), "/kml/2."))))
             {
                 CPLError(
                     CE_Failure, CPLE_AppDefined,
@@ -217,7 +221,7 @@ void KML::checkValidity()
         }
 
         nCount++;
-        /* After reading 50 * BUFSIZE bytes, and not finding whether the file */
+        /* After reading 50 * PARSER_BUF_SIZE bytes, and not finding whether the file */
         /* is KML or not, we give up and fail silently */
     } while (!nDone && nLen > 0 && validity == KML_VALIDITY_UNKNOWN &&
              nCount < 50);
@@ -370,7 +374,7 @@ void XMLCALL KML::dataHandlerValidate(void *pUserData,
     KML *poKML = static_cast<KML *>(pUserData);
 
     poKML->nDataHandlerCounter++;
-    if (poKML->nDataHandlerCounter >= BUFSIZ)
+    if (poKML->nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
@@ -535,7 +539,7 @@ void XMLCALL KML::dataHandler(void *pUserData, const char *pszData, int nLen)
         return;
 
     poKML->nDataHandlerCounter++;
-    if (poKML->nDataHandlerCounter >= BUFSIZ)
+    if (poKML->nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
diff --git a/ogr/ogrsf_frmts/lvbag/ogr_lvbag.h b/ogr/ogrsf_frmts/lvbag/ogr_lvbag.h
index c4da66721388..f54548cf22c3 100644
--- a/ogr/ogrsf_frmts/lvbag/ogr_lvbag.h
+++ b/ogr/ogrsf_frmts/lvbag/ogr_lvbag.h
@@ -57,6 +57,7 @@ using LayerVector = std::vector<std::pair<LayerType, OGRLayerUniquePtr>>;
 /************************************************************************/
 /*                           OGRLVBAGLayer                              */
 /************************************************************************/
+constexpr int PARSER_BUF_SIZE = 8192;
 
 class OGRLVBAGLayer final : public OGRAbstractProxiedLayer,
                             public OGRGetNextFeatureThroughRaw<OGRLVBAGLayer>
@@ -103,7 +104,7 @@ class OGRLVBAGLayer final : public OGRAbstractProxiedLayer,
     CPLString osAttributeString;
     bool bCollectData;
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf = std::vector<char>(PARSER_BUF_SIZE);
 
     void AddSpatialRef(OGRwkbGeometryType eTypeIn);
     void AddOccurrenceFieldDefn();
diff --git a/ogr/ogrsf_frmts/lvbag/ogrlvbaglayer.cpp b/ogr/ogrsf_frmts/lvbag/ogrlvbaglayer.cpp
index ec3127472896..d3005020f391 100644
--- a/ogr/ogrsf_frmts/lvbag/ogrlvbaglayer.cpp
+++ b/ogr/ogrsf_frmts/lvbag/ogrlvbaglayer.cpp
@@ -58,8 +58,6 @@ OGRLVBAGLayer::OGRLVBAGLayer(const char *pszFilename, OGRLayerPool *poPoolIn,
     SetDescription(CPLGetBasename(pszFilename));
 
     poFeatureDefn->Reference();
-
-    memset(aBuf, '\0', sizeof(aBuf));
 }
 
 /************************************************************************/
@@ -862,12 +860,11 @@ void OGRLVBAGLayer::ParseDocument()
             case XML_INITIALIZED:
             case XML_PARSING:
             {
-                memset(aBuf, '\0', sizeof(aBuf));
                 const unsigned int nLen = static_cast<unsigned int>(
-                    VSIFReadL(aBuf, 1, sizeof(aBuf), fp));
+                    VSIFReadL(aBuf.data(), 1, aBuf.size(), fp));
 
-                if (IsParserFinished(
-                        XML_Parse(oParser.get(), aBuf, nLen, VSIFEofL(fp))))
+                if (IsParserFinished(XML_Parse(oParser.get(), aBuf.data(), nLen,
+                                               VSIFEofL(fp))))
                     return;
 
                 break;
diff --git a/ogr/ogrsf_frmts/ods/ogrodsdatasource.cpp b/ogr/ogrsf_frmts/ods/ogrodsdatasource.cpp
index 56a6ede962a9..7768aa1d4408 100644
--- a/ogr/ogrsf_frmts/ods/ogrodsdatasource.cpp
+++ b/ogr/ogrsf_frmts/ods/ogrodsdatasource.cpp
@@ -39,6 +39,8 @@
 namespace OGRODS
 {
 
+constexpr int PARSER_BUF_SIZE = 8192;
+
 /************************************************************************/
 /*                          ODSCellEvaluator                            */
 /************************************************************************/
@@ -447,7 +449,7 @@ void OGRODSDataSource::dataHandlerCbk(const char *data, int nLen)
         return;
 
     nDataHandlerCounter++;
-    if (nDataHandlerCounter >= BUFSIZ)
+    if (nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
@@ -1300,15 +1302,15 @@ void OGRODSDataSource::AnalyseFile()
 
     VSIFSeekL(fpContent, 0, SEEK_SET);
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     do
     {
         nDataHandlerCounter = 0;
         unsigned int nLen = static_cast<unsigned int>(
-            VSIFReadL(aBuf, 1, sizeof(aBuf), fpContent));
+            VSIFReadL(aBuf.data(), 1, aBuf.size(), fpContent));
         nDone = VSIFEofL(fpContent);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
             CPLError(CE_Failure, CPLE_AppDefined,
                      "XML parsing of ODS file failed : %s at line %d, "
@@ -1441,7 +1443,7 @@ void OGRODSDataSource::dataHandlerStylesCbk(const char *data, int nLen)
         return;
 
     nDataHandlerCounter++;
-    if (nDataHandlerCounter >= BUFSIZ)
+    if (nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
@@ -1483,15 +1485,15 @@ void OGRODSDataSource::AnalyseSettings()
 
     VSIFSeekL(fpSettings, 0, SEEK_SET);
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     do
     {
         nDataHandlerCounter = 0;
         unsigned int nLen =
-            (unsigned int)VSIFReadL(aBuf, 1, sizeof(aBuf), fpSettings);
+            (unsigned int)VSIFReadL(aBuf.data(), 1, aBuf.size(), fpSettings);
         nDone = VSIFEofL(fpSettings);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
             CPLError(CE_Failure, CPLE_AppDefined,
                      "XML parsing of styles.xml file failed : %s at line %d, "
diff --git a/ogr/ogrsf_frmts/svg/ogr_svg.h b/ogr/ogrsf_frmts/svg/ogr_svg.h
index da983fa230be..bbef5aeb9e22 100644
--- a/ogr/ogrsf_frmts/svg/ogr_svg.h
+++ b/ogr/ogrsf_frmts/svg/ogr_svg.h
@@ -45,6 +45,8 @@ typedef enum
     SVG_POLYGONS,
 } SVGGeometryType;
 
+constexpr int PARSER_BUF_SIZE = 8192;
+
 /************************************************************************/
 /*                             OGRSVGLayer                              */
 /************************************************************************/
diff --git a/ogr/ogrsf_frmts/svg/ogrsvgdatasource.cpp b/ogr/ogrsf_frmts/svg/ogrsvgdatasource.cpp
index fd7d7c71cc41..0a5bafa78e13 100644
--- a/ogr/ogrsf_frmts/svg/ogrsvgdatasource.cpp
+++ b/ogr/ogrsf_frmts/svg/ogrsvgdatasource.cpp
@@ -108,7 +108,7 @@ void OGRSVGDataSource::dataHandlerValidateCbk(CPL_UNUSED const char *data,
                                               CPL_UNUSED int nLen)
 {
     nDataHandlerCounter++;
-    if (nDataHandlerCounter >= BUFSIZ)
+    if (nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
@@ -165,7 +165,7 @@ int OGRSVGDataSource::Open(const char *pszFilename)
     XML_SetElementHandler(oParser, ::startElementValidateCbk, nullptr);
     XML_SetCharacterDataHandler(oParser, ::dataHandlerValidateCbk);
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     unsigned int nLen = 0;
     int nCount = 0;
@@ -177,15 +177,15 @@ int OGRSVGDataSource::Open(const char *pszFilename)
     do
     {
         nDataHandlerCounter = 0;
-        nLen = (unsigned int)VSIFReadL(aBuf, 1, sizeof(aBuf), fp);
+        nLen = (unsigned int)VSIFReadL(aBuf.data(), 1, aBuf.size(), fp);
         nDone = VSIFEofL(fp);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
-            if (nLen <= BUFSIZ - 1)
+            if (nLen <= PARSER_BUF_SIZE - 1)
                 aBuf[nLen] = 0;
             else
-                aBuf[BUFSIZ - 1] = 0;
-            if (strstr(aBuf, "<?xml") && strstr(aBuf, "<svg"))
+                aBuf[PARSER_BUF_SIZE - 1] = 0;
+            if (strstr(aBuf.data(), "<?xml") && strstr(aBuf.data(), "<svg"))
             {
                 CPLError(
                     CE_Failure, CPLE_AppDefined,
@@ -207,7 +207,7 @@ int OGRSVGDataSource::Open(const char *pszFilename)
         }
         else
         {
-            /* After reading 50 * BUFSIZE bytes, and not finding whether the
+            /* After reading 50 * PARSER_BUF_SIZE bytes, and not finding whether the
              * file */
             /* is SVG or not, we give up and fail silently */
             nCount++;
diff --git a/ogr/ogrsf_frmts/svg/ogrsvglayer.cpp b/ogr/ogrsf_frmts/svg/ogrsvglayer.cpp
index 90026d9dc4de..45e370dd172e 100644
--- a/ogr/ogrsf_frmts/svg/ogrsvglayer.cpp
+++ b/ogr/ogrsf_frmts/svg/ogrsvglayer.cpp
@@ -480,7 +480,7 @@ void OGRSVGLayer::dataHandlerCbk(const char *data, int nLen)
         return;
 
     nDataHandlerCounter++;
-    if (nDataHandlerCounter >= BUFSIZ)
+    if (nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
@@ -539,7 +539,7 @@ OGRFeature *OGRSVGLayer::GetNextFeature()
     if (VSIFEofL(fpSVG))
         return nullptr;
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
 
     CPLFree(ppoFeatureTab);
     ppoFeatureTab = nullptr;
@@ -553,9 +553,9 @@ OGRFeature *OGRSVGLayer::GetNextFeature()
     {
         nDataHandlerCounter = 0;
         unsigned int nLen =
-            (unsigned int)VSIFReadL(aBuf, 1, sizeof(aBuf), fpSVG);
+            (unsigned int)VSIFReadL(aBuf.data(), 1, aBuf.size(), fpSVG);
         nDone = VSIFEofL(fpSVG);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
             CPLError(
                 CE_Failure, CPLE_AppDefined,
@@ -657,15 +657,16 @@ void OGRSVGLayer::LoadSchema()
     nWithoutEventCounter = 0;
     bStopParsing = false;
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     do
     {
         nDataHandlerCounter = 0;
         unsigned int nLen =
-            (unsigned int)VSIFReadL(aBuf, 1, sizeof(aBuf), fpSVG);
+            (unsigned int)VSIFReadL(aBuf.data(), 1, aBuf.size(), fpSVG);
         nDone = VSIFEofL(fpSVG);
-        if (XML_Parse(oSchemaParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oSchemaParser, aBuf.data(), nLen, nDone) ==
+            XML_STATUS_ERROR)
         {
             CPLError(
                 CE_Failure, CPLE_AppDefined,
@@ -782,7 +783,7 @@ void OGRSVGLayer::dataHandlerLoadSchemaCbk(CPL_UNUSED const char *data,
         return;
 
     nDataHandlerCounter++;
-    if (nDataHandlerCounter >= BUFSIZ)
+    if (nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
diff --git a/ogr/ogrsf_frmts/xlsx/ogrxlsxdatasource.cpp b/ogr/ogrsf_frmts/xlsx/ogrxlsxdatasource.cpp
index 5b92781e7f7f..ae4836e6c832 100644
--- a/ogr/ogrsf_frmts/xlsx/ogrxlsxdatasource.cpp
+++ b/ogr/ogrsf_frmts/xlsx/ogrxlsxdatasource.cpp
@@ -37,6 +37,8 @@
 namespace OGRXLSX
 {
 
+constexpr int PARSER_BUF_SIZE = 8192;
+
 constexpr int NUMBER_OF_DAYS_BETWEEN_1900_AND_1970 = 25569;
 constexpr int NUMBER_OF_SECONDS_PER_DAY = 86400;
 
@@ -441,7 +443,7 @@ void OGRXLSXDataSource::dataHandlerCbk(const char *data, int nLen)
         return;
 
     nDataHandlerCounter++;
-    if (nDataHandlerCounter >= BUFSIZ)
+    if (nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
@@ -1215,14 +1217,15 @@ void OGRXLSXDataSource::BuildLayer(OGRXLSXLayer *poLayer)
     stateStack[0].eVal = STATE_DEFAULT;
     stateStack[0].nBeginDepth = 0;
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     do
     {
         nDataHandlerCounter = 0;
-        unsigned int nLen = (unsigned int)VSIFReadL(aBuf, 1, sizeof(aBuf), fp);
+        unsigned int nLen =
+            (unsigned int)VSIFReadL(aBuf.data(), 1, aBuf.size(), fp);
         nDone = VSIFEofL(fp);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
             CPLError(CE_Failure, CPLE_AppDefined,
                      "XML parsing of %s file failed : %s at line %d, column %d",
@@ -1348,7 +1351,7 @@ void OGRXLSXDataSource::dataHandlerSSCbk(const char *data, int nLen)
         return;
 
     nDataHandlerCounter++;
-    if (nDataHandlerCounter >= BUFSIZ)
+    if (nDataHandlerCounter >= PARSER_BUF_SIZE)
     {
         CPLError(CE_Failure, CPLE_AppDefined,
                  "File probably corrupted (million laugh pattern)");
@@ -1398,15 +1401,15 @@ void OGRXLSXDataSource::AnalyseSharedStrings(VSILFILE *fpSharedStrings)
     stateStack[0].eVal = STATE_DEFAULT;
     stateStack[0].nBeginDepth = 0;
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     do
     {
         nDataHandlerCounter = 0;
-        unsigned int nLen =
-            (unsigned int)VSIFReadL(aBuf, 1, sizeof(aBuf), fpSharedStrings);
+        unsigned int nLen = (unsigned int)VSIFReadL(aBuf.data(), 1, aBuf.size(),
+                                                    fpSharedStrings);
         nDone = VSIFEofL(fpSharedStrings);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
             CPLError(CE_Failure, CPLE_AppDefined,
                      "XML parsing of %s file failed : %s at line %d, column %d",
@@ -1480,15 +1483,15 @@ void OGRXLSXDataSource::AnalyseWorkbookRels(VSILFILE *fpWorkbookRels)
     nWithoutEventCounter = 0;
     nDataHandlerCounter = 0;
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     do
     {
         nDataHandlerCounter = 0;
-        unsigned int nLen =
-            (unsigned int)VSIFReadL(aBuf, 1, sizeof(aBuf), fpWorkbookRels);
+        unsigned int nLen = (unsigned int)VSIFReadL(aBuf.data(), 1, aBuf.size(),
+                                                    fpWorkbookRels);
         nDone = VSIFEofL(fpWorkbookRels);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
             CPLError(CE_Failure, CPLE_AppDefined,
                      "XML parsing of %s file failed : %s at line %d, column %d",
@@ -1595,15 +1598,15 @@ void OGRXLSXDataSource::AnalyseWorkbook(VSILFILE *fpWorkbook)
     nWithoutEventCounter = 0;
     nDataHandlerCounter = 0;
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     do
     {
         nDataHandlerCounter = 0;
         unsigned int nLen =
-            (unsigned int)VSIFReadL(aBuf, 1, sizeof(aBuf), fpWorkbook);
+            (unsigned int)VSIFReadL(aBuf.data(), 1, aBuf.size(), fpWorkbook);
         nDone = VSIFEofL(fpWorkbook);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
             CPLError(CE_Failure, CPLE_AppDefined,
                      "XML parsing of %s file failed : %s at line %d, column %d",
@@ -1759,15 +1762,15 @@ void OGRXLSXDataSource::AnalyseStyles(VSILFILE *fpStyles)
     nDataHandlerCounter = 0;
     bInCellXFS = false;
 
-    char aBuf[BUFSIZ];
+    std::vector<char> aBuf(PARSER_BUF_SIZE);
     int nDone = 0;
     do
     {
         nDataHandlerCounter = 0;
         unsigned int nLen =
-            (unsigned int)VSIFReadL(aBuf, 1, sizeof(aBuf), fpStyles);
+            (unsigned int)VSIFReadL(aBuf.data(), 1, aBuf.size(), fpStyles);
         nDone = VSIFEofL(fpStyles);
-        if (XML_Parse(oParser, aBuf, nLen, nDone) == XML_STATUS_ERROR)
+        if (XML_Parse(oParser, aBuf.data(), nLen, nDone) == XML_STATUS_ERROR)
         {
             CPLError(CE_Failure, CPLE_AppDefined,
                      "XML parsing of %s file failed : %s at line %d, column %d",