CVE-2026-56288

EUVD-2026-42556

09.07.2026, 11:16

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

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	Primary	5.5 MEDIUM	LOCAL	LOW	LOW	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Base Score

CVSS 3.x

EPSS Score

Percentile: 1.81%

Affected Products (NVD)

Vendor	Product	Version
gnu	patch	𝑥 ≤ 2.8.0

𝑥

= Vulnerable software versions

Debian Releases

Debian Product

Codename

patch

bookworm	unimportant
bullseye	unimportant
forky	unimportant
sid	unimportant
trixie	unimportant

Ubuntu Releases

Ubuntu Product

Codename

patch

bionic	needs-triage
focal	needs-triage
jammy	needs-triage
noble	needs-triage
questing	ignored
resolute	needs-triage
trusty	needs-triage
xenial	needs-triage

Azure Linux Releases

Azure Package

Release

patch

Azure Linux 3.0

0:2.7.6-10.azl3

fixed

Common Weakness Enumeration

CWE-476 - NULL Pointer Dereference
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.

References

https://cert.pl/en/posts/2026/07/CVE-2026-56288

https://cgit.git.savannah.gnu.org/cgit/patch.git/

https://cgit.git.savannah.gnu.org/cgit/patch.git/commit/?id=e6d6a4e021660679d7fc9150f981d4920f722313