SumatraPDF: Signed integer overflow in the LIT header parsing causes invalid-pointer read

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

SumatraPDF is a multi-format reader for Windows. In 3.7.0.22298, LitParseHeader() in src/LitDoc.cpp computes the attacker-controlled hdrLen + nPieces * 16 section offset using signed 32-bit arithmetic without validating the complete result. When the component values make that aggregate calculation overflow to a negative value, pointer construction reaches an invalid read in LitU32(), causing deterministic application termination. The supplied evidence does not demonstrate code execution, information disclosure, arbitrary read, or integrity impact. No fixed version is available as of this review.

Source published

8 Oct 2026 22:19:46 UTC

Source modified

9 Oct 2026 15:06:40 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 3.1 · 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H