{"id":"CVE-2026-76641","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-76641","summary":"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.…","details":"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.","published":"2026-08-20T18:16:51.887","modified":"2026-08-20T18:16:51.887","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/libexpat/libexpat/commit/98599f6dcc2b460410881fe420f5f55d6bec63bf","label":"libexpat/libexpat@98599f6"},"references":[{"type":"WEB","url":"https://github.com/libexpat/libexpat/commit/98599f6dcc2b460410881fe420f5f55d6bec63bf"},{"type":"WEB","url":"https://github.com/libexpat/libexpat/pull/1331"},{"type":"WEB","url":"https://www.vulncheck.com/advisories/expat-out-of-bounds-read-via-dtdcopy"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-08-20T18:16:51.887"}}