{"id":"CVE-2026-107737","title":"SumatraPDF is a multi-format reader for Windows","summary":"SumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, and in pre-release 3.7.0.20369 when WebView2 is absent or cannot initialize, ParseProtoUrl() accepts the signed host component of an its:// URL and FindHtmlWindowById…","severity":"medium","cwe":["CWE-129"],"published":"2026-10-08","updated":"2026-10-13","sourceUpdated":"2026-10-13T17:17:17.340","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-107737","references":[{"url":"https://github.com/sumatrapdfreader/sumatrapdf/commit/596c7e26e983549a77a3a38cae1147ab73792929","label":"security-advisories@github.com"},{"url":"https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-8p34-f32f-7rmq","label":"security-advisories@github.com"},{"url":"https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-8p34-f32f-7rmq","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd","cve.org","exploit-available"],"epss":0.00182,"epssPercentile":0.07701,"ingestedAt":"2026-10-09T00:19:50.972Z","vendor":"sumatrapdfreader","product":"sumatrapdf","affected":["sumatrapdf <= 3.6.1"],"cvss":5.7,"cvssVector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-13T16:27:49.009801Z"},"cvssSource":"cna","slug":"CVE-2026-107737","body":"## Overview\n\nSumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, and in pre-release 3.7.0.20369 when WebView2 is absent or cannot initialize, ParseProtoUrl() accepts the signed host component of an its:// URL and FindHtmlWindowById() uses it directly as an index into gHtmlWindows. Opening a crafted CHM through the IE fallback backend with a negative or otherwise out-of-range window identifier can cause an out-of-bounds pointer read followed by an invalid object callback dereference and process termination. 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":"twilight","depthScore":43,"depthScoreParts":{"impact":31.4,"likelihood":0,"exploitation":12,"ransomware":0},"changes":[{"seq":221001,"id":"CVE-2026-107737","ts":1792026963478,"field":"exploit_available","old":"false","new":"true"},{"seq":221000,"id":"CVE-2026-107737","ts":1792026963478,"field":"cvss","old":null,"new":"5.7"},{"seq":220999,"id":"CVE-2026-107737","ts":1792026963478,"field":"severity","old":"none","new":"medium"}]}