UBUNTU-CVE-2026-56391

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Source
https://ubuntu.com/security/CVE-2026-56391
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56391.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-56391
Upstream
Downstream
Related
Published
2026-07-24T09:16:00Z
Modified
2026-08-31T17:16:42Z
Severity
  • 4.6 (Medium) CVSS_V4 - 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 CVSS Calculator
  • 6.1 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

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.

References

Affected packages

Ubuntu:26.04:LTS / coreutils

Package

Name
coreutils
Purl
pkg:deb/ubuntu/coreutils?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
9.7-3ubuntu2.1

Affected versions

9.*
9.5-1ubuntu4
9.7-3ubuntu1
9.7-3ubuntu2

Ecosystem specific 

{
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "gnu-coreutils",
            "binary_version": "9.7-3ubuntu2.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56391.json"