{"id":"CVE-2026-118370","aliases":[],"title":"libexpat through 2.9.0 Integer Overflow in storeAtts via attIndex and nPrefixes","titleSource":"VulnCheck","descriptionSource":"VulnCheck","products":[{"vendor":"libexpat","name":"libexpat","platforms":[],"versions":[{"version":"0","status":"affected","lessThanOrEqual":"2.9.0","versionType":"semver"}],"defaultStatus":"unaffected","source":"VulnCheck","url":"https://www.cve.org/CVERecord?id=CVE-2026-118370"}],"remediation":[],"description":"libexpat through 2.9.0 contains a signed integer overflow vulnerability in storeAtts() in lib/xmlparse.c that allows attackers to trigger out-of-bounds writes via oversized attribute counts. Attackers can supply a multi-gigabyte document with a start tag carrying over 2^30 attributes to overflow attIndex and nPrefixes, crashing applications or corrupting heap memory.","severity":"high","score":8.2,"published":"2026-10-28T02:03:19.447Z","modified":"2026-10-28T02:03:19.447Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://github.com/libexpat/libexpat/pull/1450","https://github.com/libexpat/libexpat/commit/1bac53c4fc460a03cd9860f39501c7979f6750ae","https://github.com/libexpat/libexpat/commit/621cb2c78b253ee023a86bc91d6ddb048481c04c","https://github.com/libexpat/libexpat/blob/a76b1174c1ea52abb639a4c69d52b630a8a106a2/expat/lib/xmlparse.c#L4138-L4140","https://github.com/libexpat/libexpat","https://www.vulncheck.com/advisories/libexpat-through-2.9.0-integer-overflow-in-storeatts-via-attindex-and-nprefixes"],"sources":[{"name":"CVE","id":"CVE-2026-118370","modified":"2026-10-28T02:03:19.447Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-118370"}],"assessments":[{"source":"VulnCheck","vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","score":8.2},{"source":"VulnCheck","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","score":5.9}],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-28T22:20:33.483Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}