{"id":"CVE-2026-107737","aliases":["EUVD-2026-95412","GHSA-8p34-f32f-7rmq"],"status":"published","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.","severity":{"version":"4.0","score":5.7,"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00182,"percentile":0.07852,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-129"],"published":"2026-10-08T22:34:16Z","modified":"2026-10-28T10:51:11Z","products":[{"vendor":"sumatrapdfreader","product":"sumatrapdf"}],"references":[{"url":"https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-8p34-f32f-7rmq","tags":["x_refsource_CONFIRM","exploit","advisory"]},{"url":"https://github.com/sumatrapdfreader/sumatrapdf/commit/596c7e26e983549a77a3a38cae1147ab73792929","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/107xxx/CVE-2026-107737.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-107737","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-107737","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.","status":"published","published":"2026-10-08T22:34:16.436Z","modified":"2026-10-13T16:28:11.204Z","cvss":[{"version":"4.0","score":5.7,"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","level":"medium","assessor":"cna"}],"cwes":["CWE-129"],"updated_at":"2026-11-02T13:45:14.072357Z"}],"euvd":[{"id":"EUVD-2026-95412","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.","status":"published","published":"2026-10-08T22:34:16Z","modified":"2026-10-13T16:28:11Z","cvss":[{"version":"4.0","score":5.7,"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","level":"medium"}],"updated_at":"2026-11-02T17:27:20.028612Z"}],"nvd":[{"id":"CVE-2026-107737","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.","status":"published","published":"2026-10-08T23:16:59.76Z","modified":"2026-10-13T17:17:17.34Z","cvss":[{"version":"4.0","score":5.7,"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","level":"medium","assessor":"secondary"}],"cwes":["CWE-129"],"updated_at":"2026-11-02T14:12:55.473789Z"}],"osv":[{"id":"CVE-2026-107737","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.","status":"published","published":"2026-10-08T22:34:16.436Z","modified":"2026-10-28T10:51:11.208322872Z","cvss":[{"version":"4.0","score":5.7,"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","level":"medium"}],"cwes":["CWE-129"],"updated_at":"2026-11-02T15:44:54.933106Z"}]}}