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CVE

CVE-2026-23951

SumatraPDF is a multi-format reader for Windows. All versions contain an off-by-one error in the validation code that on

SumatraPDF is a multi-format reader for Windows. All versions contain an off-by-one error in the validation code that only triggers with exactly 2 records, causing an integer underflow in the size calculation. This bug exists in PalmDbReader::GetRecord when opening a crafted Mobi file, resulting in an out-of-bounds heap read that crashes the app.

There are no published fixes at the time of publication.

MEDIUM · CVSS 5.5 EPSS 9e-05
Schedule remediation
  • Public exploit or PoC is available
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-125Out-of-bounds Read
CWE-191Integer Underflow (Wrap or Wraparound)
CWE-193Off-by-one Error
▤

Affected Products & Versions

1
sumatrapdfreader sumatrapdfall versions
⚠

Public Exploits & PoCs

1
pocgithub.com · GHSA-hj4w-c5x8-p2hvgithub.com
▣

Scoring & Timeline

5.5
MEDIUM · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD22 Jan 2026 · 01:15 AM
CVSS VectorCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
poc
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/sumatrapdfreader/sumatrapdf/blob/master/src/PalmDbReader.cppProduct
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