FreeBSD 'telnetd' Daemon Remote Buffer Overflow

critical Nessus Plugin ID 57462


The telnet server has a remote buffer overflow vulnerability.


A buffer overflow exists in libtelnet/encrypt.c in telnetd in FreeBSD 7.3 through 9.0, MIT Kerberos Version 5 Applications (aka krb5-appl) 1.0.2 and earlier, and Heimdal 1.5.1 and earlier. The vulnerability also affects any 'telnetd' service derived from the FreeBSD codebase.
Successful exploitation could allow a remote attacker to execute arbitrary code via a long encryption key.

Note that this vulnerability has been exploited in the wild since December 2011.


Upgrade to the version of FreeBSD 'telnetd' specified in the vendor's advisory.

See Also

Plugin Details

Severity: Critical

ID: 57462

File Name: telnetd_encrypt_overflow.nbin

Version: 1.76

Type: remote

Published: 1/9/2012

Updated: 7/17/2023

Configuration: Enable thorough checks

Risk Information


Risk Factor: Critical

Score: 9.4


Risk Factor: Critical

Base Score: 10

Temporal Score: 8.3

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Vulnerability Information

CPE: cpe:/o:freebsd:freebsd

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 12/23/2011

Vulnerability Publication Date: 12/23/2011

Exploitable With

Core Impact

Metasploit (Linux BSD-derived Telnet Service Encryption Key ID Buffer Overflow)

ExploitHub (EH-11-760)

Reference Information

CVE: CVE-2011-4862

BID: 51182

DSA: 2372, 2373, 2375

FREEBSD: SA-11:08.telnetd

RHSA: 2011:1851, 2011:1852