CVE-2026-25961
SumatraPDF Update MITM -> Arbitrary Code Execution
- State
- Published
- Severity
- 7.5 High
- Published
- Feb 9, 2026
- Updated
- Feb 10, 2026
- Reserved
- Feb 9, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H | GitHub_M |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
sumatrapdfsumatrapdfreader |
|
References
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