A vulnerability advisory from Dream Security said a critical Telnet vulnerability, CVE-2026-32746 with a CVSS score of 9.8, enables unauthenticated remote code execution as root in GNU inetutils telnetd and that maintainers were informed on March 11.
KEY FACTS
- Incident Pre-auth remote code execution as root
- Vulnerability CVE-2026-32746, CVSS 9.8
- Affected software GNU inetutils telnetd
- Attack vector Single connection to TCP port 23, no credentials required
The flaw is a buffer overflow in the telnetd LINEMODE Set Local Characters handler triggered during Telnet protocol negotiation. An out of bounds write can corrupt memory and allow arbitrary code execution before authentication completes.
Because telnetd often runs with root privileges successful exploitation can yield full system compromise. A single network connection to TCP port 23 is sufficient to trigger the issue and no credentials or special network position are required.
Maintainers prepared a patch the day after notification and planned a release by April 1. Immediate workarounds include migrating to SSH, disabling telnetd, running it without root privileges, or blocking port 23 and restricting access to trusted hosts.
WHY IT MATTERS
The flaw allows attackers to gain root access on affected systems without credentials. Many legacy devices and embedded systems continue to expose Telnet so the issue could affect a wide range of equipment until patches or mitigations are applied.