Organizations Warned of Exploited Linux Vulnerabilities

The flaws allow threat actors to obtain root privileges or bypass authentication via Telnet and gain shell access as root.

The US cybersecurity agency CISA on Monday expanded the Known Exploited Vulnerabilities (KEV) catalog with five flaws, including two Linux bugs.

The first Linux issue is CVE-2026-24061 (CVSS score of 9.8), a critical-severity defect in GNU Inetutils that has been exploited within days of its public disclosure last week.

It is an authentication bypass in the GNU telnetd service, which does not sanitize the USER environment variable before passing it to the login function.

The USER environment variable is used to pre-fill the username used for authentication and, because an attacker can control it via the Telnet protocol, the attacker can supply an ‘-f’ flag to bypass authentication.

An attacker can exploit the bug by sending crafted Telnet commands to set the USER variable, bypass authentication, and obtain a ...