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OpenAdvisories
Medium · 5.5 CVE-2026-23951 EUVD-2026-4205

SumatraPDF's Integer Underflow in PalmDbReader Leads to Crash

Published Jan 22, 2026 · Updated Jan 22, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
sumatrapdfreader sumatrapdf <= 3.5.2rel —

References