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VulnerabilityPublished

CVE-2026-115758: sumatrapdfreader sumatrapdf · Improper Validation of Certificate with Host Mismatch

Affects sumatrapdfreader sumatrapdfSource CVE Database V5

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Not known to be exploited · CVSS 8.2 High.

Data as of 4 Nov 2026, 23:44 UTC

CVSS 4.0 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (GitHub_M)CVSS 4.08.2
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
sumatrapdfreadersumatrapdfAffected
  • <=3.6.1
Fixed in–
GitHubsumatrapdfreader/sumatrapdfpkg:github/sumatrapdfreader/sumatrapdfOther threatsAffected
  • <=3.6.1
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Users should be cautious when updating SumatraPDF versions 3.6.1 and earlier, especially on untrusted networks. Monitoring for an official vendor advisory and applying updates once released is recommended. Due to the lack of a patch, no direct remediation is possible at this time.

Description

SumatraPDF versions 3.6.1 and earlier contain a vulnerability in the HttpGet() function where hostname validation is disabled for HTTPS update metadata and crash-symbol requests. This allows a network attacker with a trusted certificate for a malicious domain to impersonate the update server, inject malicious promotional content, and supply attacker-controlled archives to the symbol extraction process. Direct installer replacement is prevented by additional TLS validation and host restrictions. No fixed version is currently available.

References

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