CVE-2026-25961

Summary

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 Software

VendorProductVersion RangeStatus
sumatrapdfreadersumatrapdf>= 3.5.0, <= 3.5.2affected

Weaknesses

  • CWE-295: CWE-295: Improper Certificate Validation
  • CWE-494: CWE-494: Download of Code Without Integrity Check

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: total

References