CVE-2026-56391: Out‑of‑bounds Read in GNU coreutils
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 findfield() 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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 0:9.7-14.azl4 - Upgrade
Upgrade
GNU coreutils uniqto a version that resolves this vulnerability.Patch d64e35a8a4c0e4608321433e0d84d917e4e36371
Event History
Frequently Asked Questions
What is the severity of CVE-2026-56391?
CVE-2026-56391 has a risk score of 23, indicating a significant security vulnerability.
How do I fix CVE-2026-56391?
To remediate CVE-2026-56391, update your GNU coreutils to the latest version where the vulnerability has been patched.
What type of vulnerability is CVE-2026-56391?
CVE-2026-56391 is classified as an out-of-bounds read vulnerability.
Which software is affected by CVE-2026-56391?
CVE-2026-56391 affects the GNU coreutils uniq tool.
How does CVE-2026-56391 impact system security?
CVE-2026-56391 can lead to information disclosure through incorrect handling of multibyte input.