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NVD / CVE Program· CNA CERT-PL

CVE-2026-56391: Out‑of‑bounds Read in GNU coreutils

MediumCVSS 4.6 · v4.0—No exploit Fix available

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: 0.13% (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: azl4 coreutils 9.7-14.azl4 on Azure Linux 4.0 0:9.7-14.azl4.

Low priority for now. Upgrade to azl4 coreutils 9.7-14.azl4 on Azure Linux 4.0 0:9.7-14.azl4 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 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.

Published
Jul 24, 2026
Updated
Oct 24, 2026
EPSS
0.1% · 2th 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:L/VI:N/VA:L/SC:N/SI:N/SA:N

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

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  • 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
gnucoreutils

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 coreutils

    • 9.5 and later · up to and including 9.11affected

Affected versions

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

  • gnu coreutils9.5 and later · up to 9.11 inclusive

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:10coreutilsbefore 9.5-8.el10_2.19.5-8.el10_2.1
AlmaLinux:10coreutils-commonbefore 9.5-8.el10_2.19.5-8.el10_2.1
AlmaLinux:10coreutils-singlebefore 9.5-8.el10_2.19.5-8.el10_2.1
Debian:12coreutilsfrom 0—
openSUSE:Leap 16.0coreutilsbefore 9.6-160000.3.19.6-160000.3.1
openSUSE:Leap 16.0coreutils-singlebefore 9.6-160000.3.19.6-160000.3.1
openSUSE:Leap 16.0coreutils-systemdbefore 9.6-160000.3.19.6-160000.3.1
openSUSE:Leap 16.0coreutils-testsuitebefore 9.6-160000.3.19.6-160000.3.1
openSUSE:Tumbleweedcoreutilsbefore 9.11-5.19.11-5.1
Red Hat:enterprise_linux:10.2coreutilsbefore 0:9.5-8.el10_2.10:9.5-8.el10_2.1
Red Hat:enterprise_linux:10.2coreutils-debuginfobefore 0:9.5-8.el10_2.10:9.5-8.el10_2.1
Red Hat:enterprise_linux:10.2coreutils-debugsourcebefore 0:9.5-8.el10_2.10:9.5-8.el10_2.1
Red Hat:enterprise_linux:10.2coreutils-singlebefore 0:9.5-8.el10_2.10:9.5-8.el10_2.1
Red Hat:enterprise_linux:10.2coreutils-single-debuginfobefore 0:9.5-8.el10_2.10:9.5-8.el10_2.1
Red Hat:hummingbird:1coreutilsbefore 0:9.11-5.1.hum10:9.11-5.1.hum1
Red Hat:hummingbird:1coreutils-commonbefore 0:9.11-5.1.hum10:9.11-5.1.hum1
Red Hat:hummingbird:1coreutils-singlebefore 0:9.11-5.1.hum10:9.11-5.1.hum1
Rocky Linux:10coreutilsbefore 0:9.5-8.el10_2.10:9.5-8.el10_2.1
SUSE:Linux Enterprise Server 16.0coreutilsbefore 9.6-160000.3.19.6-160000.3.1
SUSE:Linux Enterprise Server 16.0coreutils-singlebefore 9.6-160000.3.19.6-160000.3.1
SUSE:Linux Enterprise Server 16.0coreutils-systemdbefore 9.6-160000.3.19.6-160000.3.1

Same product

gnu: all records

Other highest-scoring records for the same primary product.

  • CVE-2015-4042Integer overflow in the keycompare_mb function in sort.c in sort in GNU Coreutils through 8.23 might allow attackers to cause a denial of…
    40Plan
  • CVE-2014-9471The parse_datetime function in GNU coreutils allows remote attackers to cause a denial of service (crash) or possibly execute arbitrary…
    32Monitor
  • CVE-2015-4041The keycompare_mb function in sort.c in sort in GNU Coreutils through 8.23 on 64-bit platforms performs a size calculation without…
    31Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2017-18018Jan 4, 2018 · In GNU Coreutils through 8.29, chown-core.c in chown and chgrp does not prevent replacement of a plain file with a symlink during use of…
    28Monitor
  • ← EarlierCVE-2024-0684Feb 6, 2024 · Coreutils: heap overflow in split --line-bytes with very long lines
    22Monitor
  • Later →CVE-2026-56392Jul 24, 2026 · Heap-based Buffer Overflow in GNU coreutils
    7Monitor

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
azl4 coreutils 9.7-14.azl4 on Azure Linux 4.00:9.7-14.azl4 · Release NotesMicrosoft (MSRC)
almalinux:coreutils9.5-8.el10_2.1 · AlmaLinux:10Package registry (OSV)
almalinux:coreutils-common9.5-8.el10_2.1 · AlmaLinux:10Package registry (OSV)
almalinux:coreutils-single9.5-8.el10_2.1 · AlmaLinux:10Package registry (OSV)
opensuse:coreutils9.11-5.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:coreutils-single9.6-160000.3.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:coreutils-systemd9.6-160000.3.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:coreutils-testsuite9.6-160000.3.1 · openSUSE:Leap 16.0Package registry (OSV)
red hat:coreutils0:9.11-5.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:coreutils-common0:9.11-5.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:coreutils-debuginfo0:9.5-8.el10_2.1 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:coreutils-debugsource0:9.5-8.el10_2.1 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:coreutils-single0:9.11-5.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:coreutils-single0:9.5-8.el10_2.1 · Red Hat:enterprise_linux:10.2Package registry (OSV)
red hat:coreutils-single-debuginfo0:9.5-8.el10_2.1 · Red Hat:enterprise_linux:10.2Package registry (OSV)
rocky linux:coreutils0:9.5-8.el10_2.1 · Rocky Linux:10Package registry (OSV)
suse:coreutils9.6-160000.3.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:coreutils-single9.6-160000.3.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:coreutils-systemd9.6-160000.3.1 · SUSE:Linux Enterprise Server 16.0Package 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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.

Not on record for this CVE: variant or chain candidate · public bounty program.

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-125 · Out-of-bounds Read

CVSS vector

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/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.

ATT&CK techniques

—

References

Show all references (2 more)

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

All records