{"id":"CVE-2026-26054","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-26054","generatedAt":"2026-10-28T06:35:39.700Z","title":"A malformed MOBI file can use an attacker-controlled header length to bypass optional-field early returns and cause the decoder to read beyond a short heap buffer.","description":"SumatraPDF is a multi-format reader for Windows. Prior to 3.6, the MobiDoc::ParseHeader function in src/MobiDoc.cpp validates a record using kMobiHeaderMinLen but DecodeMobiDocHeader constructs a decoder sized for kMobiHeaderLen without receiving the actual remaining buffer length. A malformed MOBI file can use an attacker-controlled header length to bypass optional-field early returns and cause the decoder to read beyond a short heap buffer. Opening the crafted document can crash SumatraPDF. This issue is fixed in version 3.6.","published":"2026-09-24T17:17:05.000Z","lastModified":"2026-09-28T16:17:14.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"4.0","score":6.8,"severity":"MEDIUM","vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-125"],"affected":[],"epss":{"score":0.00209,"percentile":0.11049,"date":"2026-10-27","history":[{"date":"2026-09-25","score":0.00135,"percentile":0.02402}]},"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 (0.21%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-09-24T17:17:05.000Z","detail":{"score":"6.8","severity":"MEDIUM","publishedAt":"2026-09-24T17:17:04.553Z"},"summary":"New CVE, medium severity (CVSS 6.8)."}],"references":[{"url":"https://github.com/sumatrapdfreader/sumatrapdf/commit/24b9ce83383bbaa48b3efe00e4d30cccea126198","source":"security-advisories@github.com"},{"url":"https://github.com/sumatrapdfreader/sumatrapdf/issues/5318","source":"security-advisories@github.com"},{"url":"https://github.com/sumatrapdfreader/sumatrapdf/releases/tag/3.6rel","source":"security-advisories@github.com"},{"url":"https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-27p6-wrfp-pgm8","source":"security-advisories@github.com"},{"url":"https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-27p6-wrfp-pgm8","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-26054","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."}