CVE-2026-76641highCWE-125

CVE-2026-76641: high-severity vulnerability in libexpat

Expat Out-of-Bounds Read via dtdCopy

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21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 8.7epss 0.4%
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:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Affected products
libexpat · libexpat
Related CVEs — libexpat

In the same product, most dangerous first.

CVE-2026-113351HIGHlibexpat 2.7.2 through 2.9.0 Denial of Service via XML_ParserResetEPSS 0.5%CVE-2026-115506HIGHlibexpat through 2.9.0 Denial of Service via Billion Laughs Detection DelayEPSS 0.4%CVE-2026-117610HIGHlibexpat through 2.9.0 NULL Pointer Dereference via External Entity SubparserEPSS 0.4%CVE-2026-93990HIGHExpat before 2.8.5 Malformed UTF-16 Acceptance via Unchecked SurrogateEPSS 0.4%CVE-2026-118370HIGHlibexpat through 2.9.0 Integer Overflow in storeAtts via attIndex and nPrefixesEPSS 0.4%CVE-2026-102633HIGHlibexpat 2.7.2 through 2.8.5 Integer Overflow in expat_reallocEPSS 0.4%