What’s Vulnerable › Vulnerabilities
CVE-2026-25961: SumatraPDF Update MITM -> Arbitrary Code Execution
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2026-02-09 · updated 2026-06-17
- Weakness: CWE-295
Description
SumatraPDF is a multi-format reader for Windows. In 3.5.0 through 3.5.2, SumatraPDF's update mechanism disables TLS hostname verification (INTERNET_FLAG_IGNORE_CERT_CN_INVALID) and executes installers without signature checks. A network attacker with any valid TLS certificate (e.g., Let's Encrypt) can intercept the update check request, inject a malicious installer URL, and achieve arbitrary code execution.
Affected products
- sumatrapdfreader sumatrapdf: from 3.5 through 3.5.2
References
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