CVE-2026-56289 PUBLISHED

Loop with Unreachable Exit Condition in GNU patch

Assigner: CERT-PL
Reserved: 20.06.2026 Published: 09.07.2026 Updated: 09.07.2026

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

Metrics

CVSS Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L
CVSS Score: 4.6

Product Status

Vendor GNU
Product patch
Versions Default: unaffected
  • affected from 0 to 2.8.0 (incl.)

Credits

  • Michał Majchrowicz (AFINE Team) finder
  • Marcin Wyczechowski (AFINE Team) finder

References

Problem Types

  • CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop') CWE