Authentication Bypass in GNU Inetutils telnetd <=2.7 via USER var
CVE-2026-24061 Published on January 21, 2026
telnetd in GNU Inetutils through 2.7 allows remote authentication bypass via a "-f root" value for the USER environment variable.
Known Exploited Vulnerability
This GNU InetUtils Argument Injection Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. 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.
The following remediation steps are recommended / required by February 16, 2026: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Vulnerability Analysis
CVE-2026-24061 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. This vulnerability is known to be actively exploited by threat actors in an automatable fashion. The potential impact of an exploit of this vulnerability is considered to be critical as this vulnerability has a high impact to the confidentiality, integrity and availability of this component.
Weakness Type
What is an Argument Injection Vulnerability?
The software constructs a string for a command to 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.
CVE-2026-24061 has been classified to as an Argument Injection vulnerability or weakness.
Products Associated with CVE-2026-24061
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Affected Versions
GNU Inetutils:- Version 1.9.3, <= 2.7 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.