{"id":"CVE-2026-107729","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-107729","generatedAt":"2026-10-28T05:28:07.786Z","title":"In 3.7.0.22298, src/MobiDoc.cpp narrows the untrusted unsigned mobiHdr.hdrLen field to a signed integer for validation; values above INT_MAX become negative and bypass the upper-bound check.","description":"SumatraPDF is a multi-format reader for Windows. In 3.7.0.22298, src/MobiDoc.cpp narrows the untrusted unsigned mobiHdr.hdrLen field to a signed integer for validation; values above INT_MAX become negative and bypass the upper-bound check. When the EXTH flag is set, the original unsigned value is reused as a pointer offset, causing DecodeExthHeader() to read beyond the record buffer. Opening a crafted MOBI file can reliably terminate the application with a native access violation; no code execution, information disclosure, or integrity impact has been demonstrated. No fixed version is available as of this review.","published":"2026-10-08T23:16:58.000Z","lastModified":"2026-10-09T16:17:24.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"},"cwe":["CWE-125"],"affected":[],"epss":{"score":0.00146,"percentile":0.03788,"date":"2026-10-27","history":[{"date":"2026-10-09","score":0.00146,"percentile":0.03345}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.15%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-08T23:16:58.000Z","detail":{"score":"5.5","severity":"MEDIUM","publishedAt":"2026-10-08T23:16:58.350Z"},"summary":"New CVE, medium severity (CVSS 5.5)."}],"references":[{"url":"https://github.com/sumatrapdfreader/sumatrapdf/commit/1ef900cbad02f06353b0a0747b098ca596f7c131","source":"security-advisories@github.com"},{"url":"https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-86hq-m6hv-67h2","source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-107729","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}