CVE-2026-56288
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% 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-2021-45261Medium
An Invalid Pointer vulnerability exists in GNU patch 2.7 via the another_hunk function, which causes a Denial of Service.
- CVE-2018-6952High
A double-free exists in the another_hunk function in pch.c in GNU patch through 2.7.6. It can be triggered while processing a specially crafted patch file.
- 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-2026-115207Medium
A flaw was found in GNU patch. An attacker can achieve arbitrary file creation outside the intended working directory by enticing a user or automated workflow to apply a specially crafted patch file. Due to missing validation during automatic patch reversal, absolute file paths in patch headers are accepted rather than rejected. Consequently, the utility can create files in arbitrary locations with the permissions of the executing user.
- 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
Vulnerability data from NVD (NIST) · CISA KEV · EPSS