Vulnerability Description
Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption by processing XML with external entity parsers created via XML_ExternalEntityParserCreate. A struct size mismatch between ELEMENT_TYPE members causes storeAtts to read the attIndex member past allocated memory boundaries, resulting in failure to normalize whitespace in non-CDATA attributes or a wild pointer dereference causing a segfault. This vulnerability was introduced by the fix for CVE-2026-66046.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/libexpat/libexpat/commit/98599f6dcc2b460410881fe420f5f55d6bec
- https://github.com/libexpat/libexpat/pull/1331
- https://www.vulncheck.com/advisories/expat-out-of-bounds-read-via-dtdcopy
FAQ
What is CVE-2026-76641?
CVE-2026-76641 is a vulnerability with a CVSS score of 7.5 (HIGH). Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption by processing XML with external entity parsers created via XML_ExternalEntityParserC...
How severe is CVE-2026-76641?
CVE-2026-76641 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-76641?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.