CVE-2026-107738

SumatraPDF: Untrusted binary record offset used without lower-bound validation

MEDIUM
6.8
CVSS Score
Published: October 8, 2026 at 10:35 PM UTC
Updated: October 14, 2026 at 02:16 AM UTC
1 product affected across 1 vendorSumatrapdf

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Severity
MEDIUM6.8
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

Description

SumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, ChmFile::GetCharZ() narrows file-controlled unsigned string offsets from /#WINDOWS and /#IVB to signed integers without a lower-bound check. An offset that becomes negative can make the function read before the /#STRINGS buffer, causing 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

6.8MEDIUMGitHub_M
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-125

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