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

published 2026-10-08 31 d ago modified 2026-10-09 30 d ago also EUVD-2026-95402

cvss: 5.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.1%; EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits: 0; none known

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.

Patch / fix

links 1

github.com/sumatrapdfreader/sumatrapdf@10a8327 commit

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 30 d ago (2026-10-09)

Exploit prediction

0.12% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.5	CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected products

sumatrapdfreader sumatrapdf

Classification

Weakness

CWE-190 Integer Overflow or Wraparound

References

Sources

CVE List CVE-2026-107730
NVD CVE-2026-107730

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary