Integer Underflow (Wrap or Wraparound) Affecting sumatrapdf package, versions [,3.6)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published23 Jan 2026
- disclosed22 Jan 2026
- creditMoisés Hermo Sieira
Introduced: 22 Jan 2026
CVE-2026-23951 (opens in a new tab)How to fix?
Upgrade sumatrapdf to version 3.6 or higher.
Overview
Affected versions of this package are vulnerable to Integer Underflow (Wrap or Wraparound) via the PdbReader::Parserheader() function when processing a malformed Mobi file with exactly two records, leading to an integer underflow in the size calculation. An attacker can cause the application to crash by supplying a malicious file that triggers an out-of-bounds heap read.