SumatraPDF up to 3.6.1 HTTPS Update Validation src/base/Http_win.cpp HttpGet certificate validation

Summaryinfo

A vulnerability described as problematic has been identified in SumatraPDF up to 3.6.1. This issue affects the function HttpGet of the file src/base/Http_win.cpp of the component HTTPS Update Validation. The manipulation results in certificate validation. This vulnerability is identified as CVE-2026-115758. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability classified as problematic has been found in SumatraPDF up to 3.6.1. Affected is the function HttpGet of the file src/base/Http_win.cpp of the component HTTPS Update Validation. The manipulation with an unknown input leads to a certificate validation vulnerability. CWE is classifying the issue as CWE-295. The product does not validate, or incorrectly validates, a certificate. This is going to have an impact on integrity. CVE summarizes:

SumatraPDF is a multi-format reader for Windows. In version 3.6.1 and earlier, HttpGet() in src/base/Http_win.cpp unconditionally passes INTERNET_FLAG_IGNORE_CERT_CN_INVALID to WinINet, disabling hostname matching for HTTPS update metadata and crash-symbol requests while retaining certificate-chain validation. A network-positioned attacker with a Windows-trusted certificate for an attacker-controlled domain can impersonate the project's update host, inject promo text and a clickable URL before update metadata validation, and provide an attacker-controlled archive to ExtractSymbols(). Installer replacement is not directly possible because HttpGetToFile() validates TLS and MaybeStartUpdateDownload() restricts the download host. No fixed version is available as of this review.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-115758 since 10/23/2026. The exploitability is told to be difficult. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 11/04/2026). This vulnerability is assigned to T1587.003 by the MITRE ATT&CK project.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Name

• SumatraPDF

Version

• 3.6.0
• 3.6.1

CPE 2.3info

• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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