{"id":"CVE-2026-26054","title":"SumatraPDF is a multi-format reader for Windows","summary":"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 …","severity":"medium","cvss":6.8,"cvssVector":"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","cwe":["CWE-125"],"vendor":"sumatrapdfreader","product":"sumatrapdf","affected":["sumatrapdf < 3.6"],"published":"2026-09-24","updated":"2026-09-28","sourceUpdated":"2026-09-28T16:17:14.050","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-26054","references":[{"url":"https://github.com/sumatrapdfreader/sumatrapdf/commit/24b9ce83383bbaa48b3efe00e4d30cccea126198","label":"security-advisories@github.com"},{"url":"https://github.com/sumatrapdfreader/sumatrapdf/issues/5318","label":"security-advisories@github.com"},{"url":"https://github.com/sumatrapdfreader/sumatrapdf/releases/tag/3.6rel","label":"security-advisories@github.com"},{"url":"https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-27p6-wrfp-pgm8","label":"security-advisories@github.com"},{"url":"https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-27p6-wrfp-pgm8","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd","cve.org","exploit-available"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-28T15:33:10.549166Z"},"cvssSource":"cna","ingestedAt":"2026-09-24T17:48:30.383Z","epss":0.00209,"epssPercentile":0.11049,"slug":"CVE-2026-26054","body":"## Overview\n\nSumatraPDF 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":49,"depthScoreParts":{"impact":37.4,"likelihood":0,"exploitation":12,"ransomware":0},"changes":[{"seq":212011,"id":"CVE-2026-26054","ts":1790612181116,"field":"exploit_available","old":"false","new":"true"}]}