{"id":"CVE-2026-118370","revision":"052a8f0d5d594ff185ae6c2d2bd690a2","records":[{"revision":"052a8f0d5d594ff185ae6c2d2bd690a2","observedAt":"2026-10-28T03:51:21.076+00:00","statement":{"source":"cve-program","id":"CVE-2026-118370","aliases":[],"title":"libexpat through 2.9.0 Integer Overflow in storeAtts via attIndex and nPrefixes","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.","state":0,"publishedAt":"2026-10-28T02:03:19.447+00:00","modifiedAt":"2026-10-28T02:03:19.447+00:00","affected":[{"ecosystem":"Vendor product","name":"libexpat","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"libexpat\",\n                    \"product\": \"libexpat\",\n                    \"repo\": \"https://github.com/libexpat/libexpat\",\n                    \"packageURL\": \"pkg:github/libexpat/libexpat\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"0\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\",\n                            \"lessThanOrEqual\": \"2.9.0\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 4.0","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,"severity":"HIGH"},{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","score":5.9,"severity":"MEDIUM"}],"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"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-118370","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-118370","identifiers":["CVE-2026-118370"]},"retained":false,"historicalAffected":[]}],"coverage":[]}