{"id":"CVE-2026-107738","title":"SumatraPDF is a multi-format reader for Windows","summary":"SumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, ChmFile::GetCharZ() narrows file-controlled unsigned string offsets from /#WINDOWS and /#IVB to signed integers without a lower-bound check. An offset that becomes ne…","severity":"medium","cwe":["CWE-125"],"published":"2026-10-08","updated":"2026-10-14","sourceUpdated":"2026-10-14T02:16:58.240","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-107738","references":[{"url":"https://github.com/sumatrapdfreader/sumatrapdf/commit/62254ed6d781ceb5cd16489bb423e7f591cd72c4","label":"security-advisories@github.com"},{"url":"https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-33jg-vxm6-8mxx","label":"security-advisories@github.com"}],"tags":["nvd","cve.org"],"epss":0.0012,"epssPercentile":0.01788,"ingestedAt":"2026-10-09T00:19:50.973Z","vendor":"sumatrapdfreader","product":"sumatrapdf","affected":["sumatrapdf <= 3.6.1"],"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","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-14T01:35:46.846461Z"},"cvssSource":"cna","slug":"CVE-2026-107738","body":"## Overview\n\nSumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, ChmFile::GetCharZ() narrows file-controlled unsigned string offsets from /#WINDOWS and /#IVB to signed integers without a lower-bound check. An offset that becomes negative can make the function read before the /#STRINGS buffer, causing deterministic application termination. No broader impact is claimed beyond the advisory-supported conditions. No fixed version is available as of this review.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":37,"depthScoreParts":{"impact":37.4,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":221184,"id":"CVE-2026-107738","ts":1792030803601,"field":"cvss","old":null,"new":"6.8"},{"seq":221183,"id":"CVE-2026-107738","ts":1792030803601,"field":"severity","old":"none","new":"medium"}]}