What is CVE-2026-56289?

CVE-2026-56289 is a medium-severity vulnerability in GNU Patch, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 5.5/10. Published 2026-07-09.

How severe is CVE-2026-56289?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Vulnerability in GNU Patch

CVE-2026-56289

GNU patch is vulnerable to a denial of service (DoS) due to improper validation of hunk (single block of changes in diff) line offsets in unified-diff input. A specially crafted patch can specify an extremely large line number, causing the application to enter an effectively infinite processing loop while attempting to locate the requested position. This results in excessive CPU consumption and prevents the process from completing. An attacker can trigger this behavior by supplying a malicious patch file, causing the utility to become unresponsive and require manual termination. This issue has been fixed in the commit faba04ef4f2b410257f76c1b9dc85e350929c4b9

EPSS: 0.001 (1.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Affected products

Gnu Patch — versions 0

Weakness classification (CWE)

CWE-835 — Loop with Unreachable Exit Condition (Infinite Loop)

References

cvd@cert.pl (Third Party Advisory, third-party-advisory)
cvd@cert.pl (product, Patch)
cvd@cert.pl (Patch, patch)

Frequently asked questions

What is CVE-2026-56289?: CVE-2026-56289 is a medium-severity vulnerability in GNU Patch, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 5.5/10. Published 2026-07-09.
How severe is CVE-2026-56289?: Medium severity. CVSS v3 base score is 5.5 out of 10.