CVE-2026-23951 — Out-of-bounds Read in Sumatrapdf

CWE-125 — Out-of-bounds ReadCWE-191 — Integer Underflow (Wrap or Wraparound)CWE-193 — Off-by-one Error7 documents3 sources
Severity
5.5MEDIUMNVD
EPSS
0.0%
top 99.37%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
1
Sumatrapdfreader Sumatrapdf
Timeline
PublishedJan 22

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 vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:HExploitability: 1.8 | Impact: 3.6

Affected Packages1 packages

▶CVEListV5sumatrapdfreader/sumatrapdf3.5.2rel

🔴Vulnerability Details

1
CVEList
SumatraPDF's Integer Underflow in PalmDbReader Leads to Crash↗2026-01-22
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🕵️Threat Intelligence

5
Wiz
CVE-2026-23951 Impact, Exploitability, and Mitigation Steps | Wiz↗
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CVE-2026-23512 Impact, Exploitability, and Mitigation Steps | Wiz↗
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CVE-2026-25961 Impact, Exploitability, and Mitigation Steps | Wiz↗
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CVE-2026-25920 Impact, Exploitability, and Mitigation Steps | Wiz↗
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CVE-2026-25880 Impact, Exploitability, and Mitigation Steps | Wiz↗
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CVE-2026-23951 — Out-of-bounds Read in Sumatrapdf | cvebase