CVE-2026-24061: GNU InetUtils Argument Injection Vulnerability

In short

GNU InetUtils has a weakness classified as argument injection (CWE-88). CISA added it to its Known Exploited Vulnerabilities catalog on 2026-01-26. NVD lists CVSS 3.1 at 9.8 CRITICAL.

What it is

“GNU InetUtils contains an argument injection vulnerability in telnetd that could allow for remote authentication bypass via a "-f root" value for the USER environment variable.” — CISA KEV, retrieved 2026-11-01

“telnetd in GNU Inetutils through 2.7 allows remote authentication bypass via a "-f root" value for the USER environment variable.” — NVD, retrieved 2026-11-01

Who is affected

GNU InetUtils. NVD lists the following versions as affected:

• Gnu Inetutils: from 1.9.3 inclusive, through 2.7
• Debian Debian Linux: version 11.0

Exploitation status

CISA KEV added: 2026-01-26. Known ransomware campaign use: Not reported by CISA. Due date CISA set for US federal civilian agencies: 2026-02-16.

Scores

NVD CVSS 3.1: 9.8 CRITICAL; vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H; source [email protected].

EPSS by FIRST: 98.98%; percentile 99.93; score date 2026-10-31. EPSS estimates the probability of exploitation in the next 30 days.

CWE: CWE-88.

Timeline

CISA required action

“Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.” — CISA KEV

What to do

• Confirm whether you run GNU InetUtils and which version.
• Apply the vendor update or mitigation in the advisory.
• Follow CISA’s required action.
• Review the vendor guidance on signs of compromise.
• Track the fix through completion.

References

• Patch: https://codeberg.org/inetutils/inetutils/commit/ccba9f748aa8d50a38d7748e2e60362edd6a32cc
• Patch: https://codeberg.org/inetutils/inetutils/commit/fd702c02497b2f398e739e3119bed0b23dd7aa7b
• Mitigation, Vendor Advisory: https://lists.gnu.org/archive/html/bug-inetutils/2026-01/msg00004.html
• Third Party Advisory: https://www.vicarius.io/vsociety/posts/cve-2026-24061-detection-script-remote-authentication-bypass-in-gnu-inetutils-package
• Mitigation, Third Party Advisory: https://www.vicarius.io/vsociety/posts/cve-2026-24061-mitigation-script-remote-authentication-bypass-in-gnu-inetutils-package
• Mailing List, Third Party Advisory: https://lists.debian.org/debian-lts-announce/2026/01/msg00025.html
• Mailing List, Third Party Advisory: https://www.openwall.com/lists/oss-security/2026/01/20/2#:~:[email protected]%3A~%20USER='
• NVD detail
• CVE.org record
• CISA KEV catalog

Sources and dates

CISA Known Exploited Vulnerabilities Catalog, version 2026.10.30; retrieved 2026-11-01. CISA KEV data: CC0 1.0. No endorsement by CISA.

NVD retrieved: 2026-11-01. This product uses the NVD API but is not endorsed or certified by the NVD.

EPSS scores by FIRST; score date 2026-10-31.