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CVE-2026-24061: GNU InetUtils Argument Injection Vulnerability
CVE-2026-24061 is rated critical with a CVSS v3.1 base score of 9.8 and affects GNU InetUtils, along with 1 other product in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-01-26, which means exploitation in the wild has been observed.
Vulnerability description
telnetd in GNU Inetutils through 2.7 allows remote authentication bypass via a "-f root" value for the USER environment variable.
Severity breakdown
CVSS v3.1 9.8: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
- Attack complexity: Low. No special conditions; the attack can be repeated reliably.
- Privileges required: None. No account or prior access is needed.
- User interaction: None. No action from any user is needed.
- Scope: Unchanged. Impact stays within the vulnerable component.
- Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
- Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
- Availability impact: High. Total loss of availability; the component can be shut down.
Underlying weakness
CWE-88: Improper Neutralization of Argument Delimiters in a Command
The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string.
Affected products
- GNU Inetutils: from 1.9.3 up to and including 2.7
- Debian Linux: 11.0
References
- https://codeberg.org/inetutils/inetutils/commit/ccba9f748aa8d50a38d7748e2e60362edd6a32cc
- https://codeberg.org/inetutils/inetutils/commit/fd702c02497b2f398e739e3119bed0b23dd7aa7b
- https://lists.gnu.org/archive/html/bug-inetutils/2026-01/msg00004.html
- https://www.vicarius.io/vsociety/posts/cve-2026-24061-mitigation-script-remote-authentication-bypass-in-gnu-inetutils-package
- https://redteam.ae/blog/cve-2026-24061-inetutils-telnetd-root-bypass
- https://www.vicarius.io/vsociety/posts/cve-2026-24061-detection-script-remote-authentication-bypass-in-gnu-inetutils-package
- https://lists.debian.org/debian-lts-announce/2026/01/msg00025.html
- https://www.labs.greynoise.io/grimoire/2026-01-22-f-around-and-find-out-18-hours-of-unsolicited-houseguests/index.html
- https://www.openwall.com/lists/oss-security/2026/01/20/2#:~:text=root@...a%3A~%20USER='
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-24061
- https://www.gnu.org/software/inetutils/
- https://www.openwall.com/lists/oss-security/2026/01/20/2
- https://www.openwall.com/lists/oss-security/2026/01/20/8
- http://www.openwall.com/lists/oss-security/2026/01/22/1