CVE-2026-23951

Summary

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 Software

Weaknesses

• CWE-125: CWE-125: Out-of-bounds Read
• CWE-191: CWE-191: Integer Underflow (Wrap or Wraparound)

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: poc
  • Automatable: no
  • Technical Impact: partial

References

• https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-hj4w-c5x8-p2hv
• https://github.com/sumatrapdfreader/sumatrapdf/blob/master/src/PalmDbReader.cpp

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