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CVE-2026-23951mediumCWE-125CWE-191

SumatraPDF's Integer Underflow in PalmDbReader Leads to Crash

13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 5.5epss 0.2%
exploitation probability
0.2%top 91% of all CVEs
observed exploitation
nono source reports it
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/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H