CVE-2026-56289
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
GNU Patch is vulnerable to a denial of service (DoS) due to improper validation of hunk line offsets in unified-diff input. A specially crafted patch can specify an extremely large line number, causing an infinite processing loop and excessive CPU consumption.
Risk Assessment
An attacker can supply a malicious patch file, causing the patch utility to become unresponsive and require manual termination, potentially disrupting systems that rely on automated patching.
Recommendation
Immediately update GNU Patch to a version containing commit faba04ef4f2b410257f76c1b9dc85e350929c4b9 or later. Until updated, avoid applying patches from untrusted sources.
Other vulnerabilities in GNU Patch
See all- CVE-2015-1395High
Directory traversal vulnerability in GNU patch versions which support Git-style patching before 2.7.3 allows remote attackers to write to arbitrary files with the permissions of the target user via a .. (dot dot) in a diff file name.
- CVE-2019-20633Low
In GNU patch through version 2.7.6, there is a double free vulnerability in the another_hunk function in pch.c, which can cause a denial of service via a crafted patch file. This issue exists because of an incomplete fix for CVE-2018-6952.
- CVE-2026-56288Medium
GNU patch is vulnerable to a NULL pointer dereference when processing a specially crafted unified-diff patch file. Improper handling of consecutive end-of-file newline markers can corrupt internal hunk data structures, causing the application to pass a NULL pointer to fwrite() during patch processing.
Original NVD description (English source)
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