{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","favicon":"https://feed.craftedsignal.io/favicon-32x32.png","feed_url":"https://feed.craftedsignal.io/products/inetutils--2.7/feed.json","home_page_url":"https://feed.craftedsignal.io/","icon":"https://feed.craftedsignal.io/apple-touch-icon.png","items":[{"_cs_actors":[],"_cs_cpes":["cpe:2.3:a:gnu:inetutils:*:*:*:*:*:*:*:*","cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*"],"_cs_cves":[{"cvss":9.8,"id":"CVE-2026-24061"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["Inetutils (\u003c= 2.7)"],"_cs_severities":["critical"],"_cs_tags":["vulnerability","cve","telnet","privilege-escalation","remote-code-execution"],"_cs_type":"threat","_cs_vendors":["GNU"],"content_html":"\u003cp\u003eCVE-2026-24061 is a critical authentication bypass vulnerability affecting the Telnet daemon (telnetd) included in GNU Inetutils versions 2.7 and earlier. An attacker can exploit this flaw by supplying a specially crafted command-line argument, specifically providing a malicious string such as \u0026quot;-f root\u0026quot; within the USER parameter during the connection initiation process. This vulnerability is particularly impactful on systems like Ubuntu 24.04, where the telnetd process improperly handles user-provided arguments, leading to an unauthenticated session being upgraded to root privileges. Given the ease of exploitation, which requires no authentication and minimal complexity, this vulnerability poses a high risk to any exposed legacy Telnet services. Defenders should treat this as a priority, given that functional proof-of-concept code is publicly available, enabling trivial remote code execution with administrative authority on affected Linux systems.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker identifies a network-accessible host running a vulnerable version of the GNU Inetutils Telnet daemon.\u003c/li\u003e\n\u003cli\u003eAttacker prepares the exploit by formatting the client-side connection request with a malicious USER parameter.\u003c/li\u003e\n\u003cli\u003eAttacker executes the connection request: \u003ccode\u003eUSER=\u0026quot;-f root\u0026quot; telnet -a \u0026lt;target_ip\u0026gt;\u003c/code\u003e.\u003c/li\u003e\n\u003cli\u003eThe remote telnetd service accepts the connection and processes the crafted USER parameter during the authentication handshake.\u003c/li\u003e\n\u003cli\u003eThe service fails to validate the parameter, inadvertently executing the login process as the 'root' user.\u003c/li\u003e\n\u003cli\u003eThe session is established, providing the attacker with an interactive terminal with root-level permissions.\u003c/li\u003e\n\u003cli\u003eAttacker proceeds to execute arbitrary commands, exfiltrate data, or install persistent backdoors on the compromised host.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2026-24061 results in full system compromise. An unauthenticated remote attacker gains administrative control over the affected machine. This can lead to total loss of confidentiality, integrity, and availability, including data theft, malware deployment, and service disruption. The risk is significant for any environment utilizing Telnet for legacy management, as documented exploitation has been observed against Ubuntu 24.04 environments.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eImmediately audit network perimeter and internal infrastructure to identify and decommission any active Telnet services.\u003c/li\u003e\n\u003cli\u003eIf Telnet is strictly required, ensure the Telnet daemon is updated to a patched version beyond GNU Inetutils 2.7.\u003c/li\u003e\n\u003cli\u003eDeploy network-based intrusion detection signatures to monitor for connection attempts containing the string \u0026quot;-f\u0026quot; or similar patterns in the initial telnet handshake parameters.\u003c/li\u003e\n\u003cli\u003eImplement strict firewall rules to restrict access to TCP port 23 to only authorized management workstations.\u003c/li\u003e\n\u003cli\u003eUse the Sigma rule provided below to monitor for suspicious process execution patterns related to telnet clients being used for exploitation.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-09-02T12:42:52Z","date_published":"2026-09-02T12:42:52Z","id":"https://feed.craftedsignal.io/briefs/2026-09-cve-2026-24061-telnetd-auth-bypass/","summary":"An authentication bypass vulnerability in GNU Inetutils telnetd (CVE-2026-24061) allows unauthenticated remote attackers to gain root access via a malicious USER parameter.","title":"Authentication Bypass in GNU Inetutils Telnet Daemon (CVE-2026-24061)","url":"https://feed.craftedsignal.io/briefs/2026-09-cve-2026-24061-telnetd-auth-bypass/"}],"language":"en","title":"CraftedSignal Threat Feed - Inetutils (\u003c= 2.7)","version":"https://jsonfeed.org/version/1.1"}