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NVD / CVE Program· CNA CERT-PL

CVE-2026-56289: Loop with Unreachable Exit Condition in GNU patch

Noroxi assessment

Priority: Monitor (action score 18/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.11% (FIRST EPSS).
  • Someone with local access to the system can trigger it. No account or password is required. No special conditions are required; it is repeatable.
  • Fixed version: azl3 patch 2.7.6-10 on Azure Linux 3.0 2.7.6-10; azl3 patch 2.7.6-9 on Azure Linux 3.0 2.7.6-10.

Low priority for now. Upgrade to azl3 patch 2.7.6-10 on Azure Linux 3.0 2.7.6-10; azl3 patch 2.7.6-9 on Azure Linux 3.0 2.7.6-10 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

GNU patch is vulnerable to a denial of service (DoS) due to improper validation of hunk (single block of changes in diff) line offsets in unified-diff input. A specially crafted patch can specify an extremely large line number, causing the application to enter an effectively infinite processing loop while attempting to locate the requested position. This results in excessive CPU consumption and prevents the process from completing. An attacker can trigger this behavior by supplying a malicious patch file, causing the utility to become unresponsive and require manual termination. This issue has been fixed in the commit faba04ef4f2b410257f76c1b9dc85e350929c4b9

MediumCVSS 4.6 · v4.0—No exploit Fix available
Published
Jul 9, 2026
Updated
Oct 25, 2026
EPSS
0.1% · 1th percentile

Report tools

JSON

Action score

18

Monitor

Low priority for now.

CVSS
18 / 40 · 4.6 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · CERT-PL
4.6
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
gnupatch

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • gnu patchup to 2.8.0 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (CERT-PL). Independent of NVD's CPE analysis and usually ahead of it.

  • GNU patch

    • up to and including 2.8.0affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.24patchbefore 2.8.1-r02.8.1-r0
Debian:12patchfrom 0—
openSUSE:Leap 16.0patchbefore 2.7.6-160000.4.12.7.6-160000.4.1
openSUSE:Tumbleweedpatchbefore 2.8-3.12.8-3.1
Red Hat:hummingbird:1patchbefore 0:2.8-4.2.hum10:2.8-4.2.hum1
SUSE:Linux Enterprise Module for Basesystem 15 SP7patchbefore 2.7.6-150000.5.12.12.7.6-150000.5.12.1
SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5patchbefore 2.7.5-8.14.12.7.5-8.14.1
SUSE:Linux Micro 6.0patchbefore 2.7.6-4.12.7.6-4.1
SUSE:Linux Micro 6.1patchbefore 2.7.6-slfo.1.1_2.12.7.6-slfo.1.1_2.1
SUSE:Linux Micro 6.2patchbefore 2.7.6-160000.4.12.7.6-160000.4.1

Same product

gnu: all records

Other highest-scoring records for the same primary product.

  • CVE-2018-1000156GNU Patch version 2.7.6 contains an input validation vulnerability when processing patch files, specifically the EDITOR_PROGRAM invocation (
    33Monitor
  • CVE-2018-6951An issue was discovered in GNU patch through 2.7.6.
    33Monitor
  • CVE-2015-1395Directory traversal vulnerability in GNU patch versions which support Git-style patching before 2.7.3 allows remote attackers to write to ar
    33Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2019-20633Mar 25, 2020 · GNU patch through 2.7.6 contains a free(p_line[p_end]) Double Free vulnerability in the function another_hunk in pch.c that can cause a deni
    22Monitor
  • ← EarlierCVE-2021-45261Dec 22, 2021 · An Invalid Pointer vulnerability exists in GNU patch 2.7 via the another_hunk function, which causes a Denial of Service.
    22Monitor
  • ← EarlierCVE-2026-56288Jul 9, 2026 · NULL Pointer Dereference in GNU patch
    18Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
azl3 patch 2.7.6-10 on Azure Linux 3.02.7.6-10 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 patch 2.7.6-9 on Azure Linux 3.02.7.6-10 · CBL-Mariner ReleasesMicrosoft (MSRC)
alpine:patch2.8.1-r0 · Alpine:v3.24Package registry (OSV)
opensuse:patch2.8-3.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:patch0:2.8-4.2.hum1 · Red Hat:hummingbird:1Package registry (OSV)
suse:patch2.7.6-160000.4.1 · SUSE:Linux Micro 6.2Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • No account or password is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
A
Scope
X

Weakness class (CWE)

CWE-835 · Loop with Unreachable Exit Condition ('Infinite Loop')

CVSS vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L/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-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records