How severe is CVE-2011-4862?

No CVSS score has been assigned to CVE-2011-4862 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2011-4862?

Affected package information for CVE-2011-4862 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2011-4862?

No fixed release is recorded for CVE-2011-4862 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

How do I detect CVE-2011-4862 in my code and dependencies?

Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

How do I mitigate CVE-2011-4862 if there is no patch (or I can't update yet)?

Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Is CVE-2011-4862 actively exploited in the wild?

Yes. There are 10 known exploit references for CVE-2011-4862, including 3 documented proof-of-concept exploits on Exploit-DB and 6 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2011-4862?

CVE-2011-4862 has an EPSS (Exploit Prediction Scoring System) score of 95.1%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2011-4862?

CVE-2011-4862 is classified as CWE-120 (CWE-120). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2011-4862 published, and has it been updated?

CVE-2011-4862 was published on December 25, 2011 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

Not in CISA KEV

CVE-2011-4862 — Red Hat

CVE-2011-4862 is a CWE-120 vulnerability. 10 public exploit references exist, so weaponization risk is real. No vendor fix is recorded yet; mitigation options are listed below.

Published

Dec 25, 2011

Updated

Apr 10, 2026

Affected

10 products

Patched

See advisory

Exploits

10 known

Exploitation data as of Oct 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

95.1%probability of exploitation in next 30 days

Very High Risk+0.08%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Description

Buffer overflow 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, Heimdal 1.5.1 and earlier, GNU inetutils, and possibly other products allows remote attackers to execute arbitrary code via a long encryption key, as exploited in the wild in December 2011.

Affected Products

10 products · 21 configurations

debian linuxdebian

3 versions

5.06.07.0

fedorafedoraproject

2 versions

1516

freebsdfreebsd

≥ 7.3 && ≤ 9.0

range

Application

inetutilsgnu

< 1.9

range

Application

heimdalheimdal_project

≤ 1.5.1

range

Application

krb5-applmit

≤ 1.0.2

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-18280remotelinux✓ Verified

TelnetD encrypt_keyid - Function Pointer Overwrite

by NighterMan & BatchDrake · Dec 26, 2011

Exploit-DB Source

EDB-18368remotelinux✓ Verified

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

by Metasploit · Jan 14, 2012

Exploit-DB Source

EDB-18369remotebsd✓ Verified

FreeBSD - Telnet Service Encryption Key ID Buffer Overflow (Metasploit)

by Metasploit · Jan 14, 2012

Exploit-DB Source

Detection & mitigation playbook

Vulnerability

Detect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2011-4862 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatCritical

A buffer overflow flaw was found in the MIT krb5 telnet daemon (telnetd) as shipped with all supported versions of Red Hat Enterprise Linux. A remote attacker who can access the telnet port of a target machine could use this flaw to execute arbitrary code as root. While we are aware of public exploits for this issue…

Product	Fixed in	Advisory
Red Hat Enterprise Linux 3 Extended Lifecycle Support	`krb5-0:1.2.7-73`	RHSA-2011:1853
Red Hat Enterprise Linux 4	`krb5-0:1.3.4-65.el4`	RHSA-2011:1851
Red Hat Enterprise Linux 6	`krb5-appl-0:1.0.1-7.el6_2`	RHSA-2011:1852
Red Hat Enterprise Linux 6.0 EUS - Server Only	`krb5-appl-0:1.0.1-1.el6_0.1`	RHSA-2011:1854

Frequently Asked Questions

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CVE-2011-4862 — Red Hat

EPSS Exploitation Probability

Description

Affected Products

Detection & mitigation playbook

Detect

Remediation status

Mitigate without a patch

Fixing This On Your OS

Frequently Asked Questions

Is CVE-2011-4862 in your dependencies?