---
id: CVE-2026-56288
title: >-
  GNU patch is vulnerable to a NULL pointer dereference when processing a
  specially crafted unified-diff patch file
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 (single block of changes
  in diff) d…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-476
vendor: gnu
product: patch
affected:
  - patch <= 2.8.0
published: '2026-07-09'
updated: '2026-07-13'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56288'
references:
  - url: 'https://cert.pl/en/posts/2026/07/CVE-2026-56288'
    label: cvd@cert.pl
  - url: 'https://cgit.git.savannah.gnu.org/cgit/patch.git/'
    label: cvd@cert.pl
  - url: >-
      https://cgit.git.savannah.gnu.org/cgit/patch.git/commit/?id=e6d6a4e021660679d7fc9150f981d4920f722313
    label: cvd@cert.pl
tags:
  - nvd
epss: 0.00168
epssPercentile: 0.05309
ingestedAt: '2026-07-13T14:27:27.150Z'
---

## Overview

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

## Affected

- `patch <= 2.8.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.