commit 9939d60f01ff598134628ea64b9b65d4b84209ce
Author: Tomas Korbar <tkorbar@redhat.com>
Date:   Mon Feb 21 17:09:17 2022 +0100

    CVE-2021-46143

diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index e743f78..1371f61 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -4501,11 +4501,25 @@ doProlog(XML_Parser parser,
     case XML_ROLE_GROUP_OPEN:
       if (prologState.level >= groupSize) {
         if (groupSize) {
+          /* Detect and prevent integer overflow */
+          if (parser->m_groupSize > (unsigned int)(-1) / 2u) {
+            return XML_ERROR_NO_MEMORY;
+          }
+
           char *temp = (char *)REALLOC(groupConnector, groupSize *= 2);
           if (temp == NULL)
             return XML_ERROR_NO_MEMORY;
           groupConnector = temp;
           if (dtd->scaffIndex) {
+            /* Detect and prevent integer overflow.
+             * The preprocessor guard addresses the "always false" warning
+             * from -Wtype-limits on platforms where
+             * sizeof(unsigned int) < sizeof(size_t), e.g. on x86_64. */
+#if UINT_MAX >= SIZE_MAX
+            if (parser->m_groupSize > (size_t)(-1) / sizeof(int)) {
+              return XML_ERROR_NO_MEMORY;
+            }
+#endif
             int *temp = (int *)REALLOC(dtd->scaffIndex,
                           groupSize * sizeof(int));
             if (temp == NULL)