CVE-2026-25961: SumatraPDF Update MITM -> Arbitrary Code Execution
sumatrapdfreader · sumatrapdf
Affected: sumatrapdfreader · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 39% of scored CVEs
DescriptionCVE.org
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 products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- sumatrapdfreader · sumatrapdf>= 3.5.0, <= 3.5.2
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- sumatrapdfreader
- Published
- February 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-25961 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.