PT-2026-3887 · Unknown · Sumatrapdf

Ub1Cu0 · CVE-2026-23951 · Published 2026-01-22 · Updated 2026-02-17

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions SumatraPDF (affected versions not specified)

Description SumatraPDF, a multi-format reader for Windows, contains an off-by-one error in the validation code that triggers only with exactly two records. This error causes an integer underflow in the size calculation within the PalmDbReader::GetRecord function when opening a crafted Mobi file. This results in an out-of-bounds heap read, leading to application crashes. The issue may potentially lead to remote code execution via malicious PDF files.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

RCE

Integer Underflow

Out of bounds Read

Weakness Enumeration

CWE-191

CWE-193

CWE-125

Related Identifiers

CVE-2026-23951

GHSA-HJ4W-C5X8-P2HV

Affected Products

Sumatrapdf

References · 11

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23951.json · Exploit
• https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-hj4w-c5x8-p2hv · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-23951 · Security Note
• https://osv.dev/vulnerability/CVE-2026-23951 · Vendor Advisory
• https://github.com/sumatrapdfreader/sumatrapdf/blob/master/src/PalmDbReader.cpp · Note
• https://t.me/cveNotify/152209 · Telegram Post
• https://t.me/CVEtracker/42715 · Telegram Post
• https://t.me/cveNotify/149502 · Telegram Post
• https://twitter.com/VulmonFeeds/status/2014156389485072657 · Twitter Post
• https://twitter.com/CVEnew/status/2014153671500792010 · Twitter Post
• https://twitter.com/lsof/status/2014166681388491123 · Twitter Post