Vulnerability Details CVE-2026-23951
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 2.3%
CVSS Severity
CVSS v3 Score 5.5
References
Products affected by CVE-2026-23951
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cpe:2.3:a:sumatrapdfreader:sumatrapdf:-