{"id":"CVE-2026-77214","aliases":[],"title":"libexpat Heap Buffer Over-read in xmlparse.c via XML_ParseBuffer","titleSource":"VulnCheck","descriptionSource":"VulnCheck","products":[{"vendor":"libexpat","name":"libexpat","platforms":[],"versions":[{"version":"0","status":"affected","lessThanOrEqual":"2.8.5","versionType":"semver"},{"version":"13c5f63a7f1c52c2feee3b16a1134d4fb68e9ea0","status":"unaffected","versionType":"git"}],"defaultStatus":"unaffected","source":"VulnCheck","url":"https://www.cve.org/CVERecord?id=CVE-2026-77214"}],"remediation":[],"description":"libexpat before commit 13c5f63 contains a heap buffer over-read vulnerability in xmlparse.c. XML_ParseBuffer advances the parse buffer end with parser->m_bufferEnd += len using a caller-supplied length that is not validated against the allocated buffer size, so repeated XML_ParseBuffer calls move m_bufferEnd past the end of the heap allocation and subsequent parsing reads out of bounds. Reaching this path requires a parse buffer to already be present; otherwise XML_ParseBuffer returns XML_ERROR_NO_BUFFER. A buffer is present after a prior call to XML_GetBuffer, either directly (the common case) or indirectly through a prior XML_Parse call that allocates the buffer internally. The over-read discloses adjacent heap memory to the calling application, recovering heap pointers, libc function pointers, and code pointers sufficient to defeat ASLR and build further exploitation primitives.","severity":"high","score":8.3,"published":"2026-10-07T14:35:42.794Z","modified":"2026-10-27T10:14:34.918Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://github.com/libexpat/libexpat/pull/1393","https://github.com/libexpat/libexpat/commit/13c5f63a7f1c52c2feee3b16a1134d4fb68e9ea0","https://www.vulncheck.com/advisories/libexpat-heap-buffer-over-read-in-xmlparse-c-via-xml-parsebuffer"],"sources":[{"name":"CVE","id":"CVE-2026-77214","modified":"2026-10-27T10:14:34.918Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-77214"}],"assessments":[{"source":"VulnCheck","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N","score":8.3},{"source":"VulnCheck","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L","score":8.2}],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-28T20:05:31.497Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}