Submit #778638: michaelrsweet mxml 4.0.4 Heap-based Buffer Overflowinfo

Titlemichaelrsweet mxml 4.0.4 Heap-based Buffer Overflow
DescriptionWhile fuzzing the latest version of mxml using SynFuzz and AddressSanitizer, I discovered a heap-buffer-overflow (specifically, an out-of-bounds read with a negative offset) in the index_sort function within mxml-index.c. The vulnerability is triggered when a specifically malformed XML structure is parsed and subsequently passed to mxmlIndexNew to build an index. During the node sorting phase, an array pointer or index appears to decrement past the starting boundary of the allocated node array, resulting in an 8-byte read before the allocated 128-byte heap region. https://github.com/michaelrsweet/mxml/issues/350
Source⚠️ https://github.com/michaelrsweet/mxml/issues/350
User
 MTHG (UID 83728)
Submission03/12/2026 13:31 (17 days ago)
Moderation03/27/2026 17:23 (15 days later)
StatusAccepted
VulDB entry353963 [mxml up to 4.0.4 mxmlIndexNew mxml-index.c index_sort tempr stack-based overflow]
Points20

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