A critical security vulnerability, codenamed CVE-2026-32746, has been discovered in the GNU InetUtils telnet daemon (telnetd) allowing unauthenticated attackers to execute code remotely (even with root). The vulnerability has a CVSS score of 9.8/10.0 and is considered extremely dangerous as it does not require any authentication.
Vulnerability in Telnetd
CVE -2026-32746 concerns a buffer overflow caused by an out-of-bounds write in the LINEMODE Set Local Characters (SLC) suboption handler. Israeli cybersecurity firm Dream discovered and reported the vulnerability on 11, 2026, noting that it affects all versions of the Telnet service implementation up to version 2.7.
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According to Dream, an unauthorized attacker can exploit the vulnerability by sending specially crafted messages during the initial connection handshake, before the login prompt. Successful exploitation could lead to code execution with root, as telnetd typically runs with root privileges.
As security researcher Adiel Sol from Dream, an unauthorized attacker can trigger the vulnerability by connecting to port 23.No login, as the error occurs during option negotiation, before the login prompt.
Impacts and risks from vulnerability CVE-2026-32746
Successful exploitation could lead to a complete system compromise if telnetd is run with root privileges. This, in turn, could open the door to a variety of actions, including the deployment of persistent backdoors, data extraction , and lateral movement using compromised hosts as pivot points.
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The vulnerability affects GNU inetutils versions up to 2.7 , potentially exposing thousands of legacy Linux/Unix hosts with telnetd enabled .
The disclosure comes nearly two months after another critical security vulnerability was disclosed in GNU InetUtils telnetd (CVE-2026-24061, CVSS score: 9.8) that could be exploited to gain root access to a targeted system. The vulnerability has been exploited by cybercriminals, according to CISA.
Protection measures and security recommendations
In the absence of a fix available, experts recommend immediately disabling the telnetd service if it is not needed. If it is required, it should be run without root privileges . In addition, it is recommended to block port 23 at the network perimeter and host-based firewall level to restrict access.
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A fix for the vulnerability is expected to be available no later than April 1, 2026.Until then, organizations should take immediate preventive measures to protect their systems from potential attacks, according to The Hacker News.
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