---
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: none
cwe:
  - CWE-129
published: '2026-10-08'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T23:16:59.900'
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
tags:
  - nvd
ingestedAt: '2026-10-09T00:19:50.972Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.