CVE-2026-56288
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
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.
Risk Assessment
An attacker can trigger this condition with a malicious patch file, causing the utility to crash and resulting in a denial of service (DoS) on the affected system.
Recommendation
Update GNU patch to a version containing commit e6d6a4e021660679d7fc9150f981d4920f722313 or later, which fixes this vulnerability.
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-2026-56289Medium
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.
Original NVD description (English source)
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 (single block of changes in diff) data structures, causing the application to pass a NULL pointer to fwrite() during patch processing. An attacker can trigger this condition with a malicious patch file, causing the utility to crash and resulting in a denial of service. This issue has been fixed in the commit e6d6a4e021660679d7fc9150f981d4920f722313