CVE-2026-26054: sumatrapdfreader sumatrapdf · Out-of-bounds Read
Affects sumatrapdfreader sumatrapdfSource CVE Database V5
Not known to be exploited · CVSS 6.8 Medium : upgrade to 3.6 when convenient.
Data as of 6 Nov 2026, 23:24 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.6
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 24 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 6 Nov 2026.
What to do
Upgrade sumatrapdf and sumatrapdfreader/sumatrapdf to 3.6.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| sumatrapdfreadersumatrapdf | Affected
| Fixed in
|
GitHubsumatrapdfreader/sumatrapdfpkg:github/sumatrapdfreader/sumatrapdfOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
This vulnerability is fixed in SumatraPDF version 3.6. Users should upgrade to version 3.6 or later to remediate this issue. No additional mitigation steps are indicated.
Description
SumatraPDF is a multi-format reader for Windows. Prior to 3.6, the MobiDoc::ParseHeader function in src/MobiDoc.cpp validates a record using kMobiHeaderMinLen but DecodeMobiDocHeader constructs a decoder sized for kMobiHeaderLen without receiving the actual remaining buffer length. A malformed MOBI file can use an attacker-controlled header length to bypass optional-field early returns and cause the decoder to read beyond a short heap buffer. Opening the crafted document can crash SumatraPDF. This issue is fixed in version 3.6.
References
- github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-27p6-wrfp-pgm8 (opens in a new tab)
- github.com/sumatrapdfreader/sumatrapdf/issues/5318 (opens in a new tab)
- github.com/sumatrapdfreader/sumatrapdf/commit/24b9ce83383bbaa48b3efe00e4d30cccea126198 (opens in a new tab)
- github.com/sumatrapdfreader/sumatrapdf/releases/tag/3.6rel (opens in a new tab)