Is CVE-2026-76641 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-76641?

CVE-2026-76641 has a CVSS v3 severity of HIGH (7.5).

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CVE-2026-76641

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.