Out-of-bounds Read in Sumatrapdfreader Sumatrapdf
CVE-2026-107731
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Sumatrapdfreader Sumatrapdf — versions <= 3.7.0.22298
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-107731?
- CVE-2026-107731 is a medium-severity vulnerability in Sumatrapdfreader Sumatrapdf, classified under Out-of-bounds Read. CVSS score: 5.5/10. Published 2026-10-08.
- How severe is CVE-2026-107731?
- Medium severity. CVSS v3 base score is 5.5 out of 10.