VulnerabilityAnalyzed

CVE-2026-23951

This bug exists in PalmDbReader::GetRecord when opening a crafted Mobi file, resulting in an out-of-bounds heap read that crashes the app.

MEDIUM 5.5EPSS 0.21%

Does this matter?

Lower severity and a low EPSS score (0.21%). Track it; it rarely justifies an emergency change on its own.

Description

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.

CVSS 3.1: 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS: 0.21% probability · 11th percentile
CISA KEV: Not listed
Weakness: CWE-125, CWE-191, CWE-193
Affected: sumatrapdfreader/sumatrapdf
Source: security-advisories@github.com

References

https://github.com/sumatrapdfreader/sumatrapdf/blob/master/src/PalmDbReader.cppProduct
https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-hj4w-c5x8-p2hvExploit, Vendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.