{"schemaVersion":3,"id":"CVE-2026-107737","aliases":[],"status":"published","duplicateOf":null,"title":"SumatraPDF CHM `its://` signed index causes an out-of-bounds object lookup","description":"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() 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.","dates":{"published":"2026-10-08T22:34:16.436Z","modified":"2026-10-13T16:28:11.204Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":5.7,"severity":"medium","version":"4.0","versionLabel":"v4.0","source":"CVE.org","vector":"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","computed":false,"selection":"backend-summary"},"metrics":[{"version":"4.0","versionLabel":"v4.0","source":"CVE.org","score":5.7,"severity":"medium","vector":"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","exploitability":null,"impact":null,"computed":false},{"version":"4.0","versionLabel":"v4.0","source":"NVD","score":5.7,"severity":"medium","vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.0012,"percentile":0.01702,"severity":"low","asOf":"2026-10-22T00:00:00.000Z","change":{"pp":null,"baselineDate":null,"baselineScore":null},"history":[{"date":"2026-10-09T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-22T00:00:00.000Z","score":0.0012,"percentile":0.01702}],"last30":[{"date":"2026-10-09T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.0012,"percentile":null},{"date":"2026-10-22T00:00:00.000Z","score":0.0012,"percentile":0.01702}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-129","name":"Improper 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