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.
History

Tue, 13 Oct 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 08 Oct 2026 23:30:00 +0000

Type Values Removed Values Added
First Time appeared Sumatrapdfreader
Sumatrapdfreader sumatrapdf
Vendors & Products Sumatrapdfreader
Sumatrapdfreader sumatrapdf

Thu, 08 Oct 2026 22:45:00 +0000

Type Values Removed Values Added
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.
Title SumatraPDF CHM `its://` signed index causes an out-of-bounds object lookup
Weaknesses CWE-129
References
Metrics cvssV4_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'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-10-08T22:34:16.436Z

Updated: 2026-10-13T16:28:11.204Z

Reserved: 2026-10-08T17:21:52.977Z

Link: CVE-2026-107737

cve-icon Vulnrichment

Updated: 2026-10-13T16:28:06.673Z

cve-icon NVD

Status : Deferred

Published: 2026-10-08T23:16:59.760

Modified: 2026-10-13T17:17:17.340

Link: CVE-2026-107737

cve-icon Redhat

No data.