CVE-2026-107731

SumatraPDF: LIT parser range-validation flaws cause invalid-pointer reads and denial of service

MEDIUM
5.5
CVSS Score
Published: October 8, 2026 at 10:20 PM UTC
Updated: October 9, 2026 at 04:17 PM UTC
1 product affected across 1 vendorSumatrapdf

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

Description

SumatraPDF is a multi-format reader for Windows. In 3.7.0.22298, four independently reachable range-validation variants in src/LitDoc.cpp allow file-controlled offsets and sizes to overflow, narrow to negative values, or wrap before incomplete bounds checks. The affected calculations include contentOffset, the directory expression dirOff64 + dirLen64, and the decoded-section offset + size, along with secondary-header range handling. Opening a crafted LIT file that reaches one of these variants can cause invalid pointer reads and deterministic application termination. No broader impact is claimed beyond the advisory-supported conditions. No fixed version is available as of this review.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.5MEDIUMGitHub_M
Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-125

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