DoS in GNU Patch via Unrealistic Hunk Offsets
CVE-2026-56289 Published on July 9, 2026
Loop with Unreachable Exit Condition in GNU patch
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
Weakness Type
What is an Infinite Loop Vulnerability?
The program contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. If the loop can be influenced by an attacker, this weakness could allow attackers to consume excessive resources such as CPU or memory.
CVE-2026-56289 has been classified to as an Infinite Loop vulnerability or weakness.
Products Associated with CVE-2026-56289
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Affected Versions
GNU patch:- Before and including 2.8.0 is affected.