{"id":"CVE-2026-124317","state":"PUBLISHED","title":"libexpat through 2.10.0 Out-of-Bounds Read via unknown_toUtf8 and unknown_toUtf16","description":"libexpat through 2.10.0 contains an out-of-bounds read vulnerability in unknown_toUtf8() and unknown_toUtf16() in xmltok.c when handling application-registered unknown encodings. Attackers can supply a document ending in a truncated multibyte sequence so the convert callback reads past the parse buffer, leaking adjacent memory or crashing applications.","publishedAt":"2026-11-07T14:17:57.180Z","updatedAt":"2026-11-07T14:17:57.180Z","severity":{"score":6.3,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N","source":"VulnCheck"},"assigner":"VulnCheck","products":["libexpat libexpat"],"affected":[{"vendor":"libexpat","product":"libexpat","packageURL":"pkg:github/libexpat/libexpat","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"2.10.0","versionType":"semver"}],"repo":"https://github.com/libexpat/libexpat"}],"references":["https://github.com/libexpat/libexpat/pull/1492","https://github.com/libexpat/libexpat/blob/a70841d9ffa64ddde29ab824ed6305035ebe4c47/expat/lib/xmltok.c#L1274-L1322","https://github.com/libexpat/libexpat","https://www.vulncheck.com/advisories/libexpat-through-2.10.0-out-of-bounds-read-via-unknown-toutf8-and-unknown-toutf16"],"weaknesses":["CWE-126"],"ingestedAt":"2026-11-07T14:22:06.444Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/124xxx/CVE-2026-124317.json","commit":"5d35b2472b54e06eae81b39f4b7558075966f320","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-124317","state":"PUBLISHED","datePublished":"2026-11-07T14:17:57.180Z","dateUpdated":"2026-11-07T14:17:57.180Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-11-07T12:27:50.865Z"},"containers":{"cna":{"title":"libexpat through 2.10.0 Out-of-Bounds Read via unknown_toUtf8 and unknown_toUtf16","descriptions":[{"lang":"en","value":"libexpat through 2.10.0 contains an out-of-bounds read vulnerability in unknown_toUtf8() and unknown_toUtf16() in xmltok.c when handling application-registered unknown encodings. Attackers can supply a document ending in a truncated multibyte sequence so the convert callback reads past the parse buffer, leaking adjacent memory or crashing applications."}],"affected":[{"vendor":"libexpat","product":"libexpat","packageURL":"pkg:github/libexpat/libexpat","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"2.10.0","versionType":"semver"}],"repo":"https://github.com/libexpat/libexpat"}],"references":[{"url":"https://github.com/libexpat/libexpat/pull/1492","tags":["patch","issue-tracking"]},{"url":"https://github.com/libexpat/libexpat/blob/a70841d9ffa64ddde29ab824ed6305035ebe4c47/expat/lib/xmltok.c#L1274-L1322","tags":["technical-description"]},{"url":"https://github.com/libexpat/libexpat","tags":["product"]},{"url":"https://www.vulncheck.com/advisories/libexpat-through-2.10.0-out-of-bounds-read-via-unknown-toutf8-and-unknown-toutf16","name":"VulnCheck Advisory: libexpat through 2.10.0 Out-of-Bounds Read via unknown_toUtf8 and unknown_toUtf16","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N","attackVector":"NETWORK","attackComplexity":"HIGH","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.3,"baseSeverity":"MEDIUM"}},{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"LOW","baseScore":4.8,"baseSeverity":"MEDIUM"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-126","lang":"en","description":"Buffer Over-read","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-11-07T14:17:57.180Z"},"datePublic":"2026-11-06T00:00:00.000Z","cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:libexpat_project:libexpat:*:*:*:*:*:*:*:*","versionEndIncluding":"2.10.0"}]}]}],"credits":[{"lang":"en","value":"Oğuzhan Demirbaş","type":"finder"},{"lang":"en","value":"Sebastian Pipping","type":"remediation developer"}],"x_generator":{"engine":"vulncheck-endgame"}}}}}