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Coreutils CVE-2026-56391

| EUVDEUVD-2026-48524 MEDIUM
Out-of-bounds Read (CWE-125)
2026-07-24 CERT-PL GHSA-7xvj-m9x7-qgxq
Buffer Overflow Information Disclosure Coreutils Gnu
4.6
CVSS 4.0 · Vendor: CERT-PL
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Vulnerability Assessment

Weakness
CWE
CWE-125
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, read limits
MITRE ATT&CK

1 technique across 1 tactic: Collection

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

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This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Jul 26, 2026

Out-of-bounds read in GNU coreutils uniq allows attackers with crafted multibyte input and the -w option to crash the utility and potentially leak adjacent heap memory. Affects versions 9.5 through 9.11. No active exploitation or public exploit code is known, but a patch exists.

Affected VersionsENISA

coreutils 9.5 ≤9.11

Affected Packages

euvd coreutils no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

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  • Exploit and PoC references, threat intelligence from 22 sources
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Severity by source

Vendor (CERT-PL) PRIMARY 4.6 MEDIUM
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N
SUSE 6.1 MEDIUM
AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
Red Hat 6.1 MEDIUM

Primary rating from Vendor (CERT-PL).

CVSS VectorVendor: CERT-PL

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
Active
Vulnerable system: Confidentiality
Low
Vulnerable system: Integrity
None
Vulnerable system: Availability
Low
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

DescriptionCVE.org

GNU coreutils uniq is vulnerable to an out‑of‑bounds read due to incorrect handling of multibyte input when the -w (--check-chars) option is used. The find_field() function miscalculates the byte length of characters by repeatedly processing a fixed pointer instead of advancing through the input, resulting in an inflated length value. This incorrect length is later used in a memcmp operation, causing reads beyond the allocated buffer when processing crafted multibyte input.

When running GNU coreutils uniq with attacker-provided arguments, this behavior leads to a crash and potential adjacent heap memory exposure.

This issue has been fixed in the commit d64e35a8a4c0e4608321433e0d84d917e4e36371.

Threat Intelligence Overview

EPSS Score
0.1%
Top 97% exploitable
Social Media
1
Sightings
Data Quality
8 sources
Confidence: High
EUVD 🇯🇵JVN NVD CVE.org EPSS Vulnrichment MSRC Vendor CIRCL VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

23
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +23
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

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Same weakness CWE-125 – Out-of-bounds Read

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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SLES15-SP5-CHOST-BYOS-SAP-CCloud Affected
SLES15-SP6-CHOST-BYOS Affected
SLES15-SP6-CHOST-BYOS-Aliyun Affected
SLES15-SP6-CHOST-BYOS-Azure Affected
SLES15-SP6-CHOST-BYOS-EC2 Affected

References

Advisories & patches
PATCH https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=d64e35a8a4c0e4608321433e0d84d917e4e36371 ADVISORY https://access.redhat.com/errata/RHSA-2026:46515 ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-56391 ADVISORY https://seclists.org/oss-sec/2026/q3/276 ADVISORY https://ubuntu.com/security/notices/USN-8697-1 ADVISORY https://vuldb.com/vuln/382878 REF https://cert.pl/en/posts/2026/07/CVE-2026-56391 REF https://git.savannah.gnu.org/cgit/coreutils.git/

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