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Fencer Vulns
medium 5.5

CVE-2026-56288 json

NULL Pointer Dereference in GNU patch

published 2026-07-09 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-42556 , GHSA-m3j2-9m66-r96h , JLSEC-2026-1260

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

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) 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

Patch / fix

  • patch hummingbird 1 2.8-4.3.hum1

red hat advisories RHSA-2026:38019

  • patch Linux Micro 6.0 2.7.6-4.1
  • patch Linux Micro 6.1 2.7.6-slfo.1.1_2.1
  • patch SLE Module for Basesystem 15 SP7 2.7.6-150000.5.12.1
  • patch SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 2.7.6-160000.4.1
  • patch SLES LTSS Extended Security 12 SP5 2.7.5-8.14.1

suse advisories SUSE-SU-2026:23210-1SUSE-SU-2026:22905-1SUSE-SU-2026:3161-1SUSE-SU-2026:22604-1SUSE-SU-2026:22651-1SUSE-SU-2026:2922-1

  • patch openSUSE Leap 16.0 2.7.6-160000.4.1
  • patch openSUSE Tumbleweed 2.8-3.1

opensuse advisories openSUSE-SU-2026:21332-1openSUSE-SU-2026:11260-1

  • patch Alpine 3.24 2.8.1-r0

alpine advisories ALPINE-CVE-2026-56288

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • patch Azure Linux 3.0 2.7.6-10

azure linux advisories AZL-92154

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-56288 updated cvss 5.0

patch: GNU patch: Denial of Service via specially crafted patch file

  • Red Hat Hardened Images patch 2.8-4.3.hum1
    fixed: vendor fix RHSA-2026:38019

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.11% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 4.6 CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CNA 4.0 4.6 CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
julia patch_jll
all versions
 no fix listed

Affected products

  • GNU patch

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.