CVE-2011-4862

CRITICAL ⚠ Exploit

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 po...

Affects 10 products across 8 vendors.

CVSS 2.010.0
EPSS95.1%
Percentile100th
PatchUnknown
CVSS Vector — Plain English Remotely exploitable over the network, low complexity.
CWE Weakness Definitions
CWE-120: Buffer Copy without Checking Size (Classic Buffer Overflow)

Program copies data to a buffer without verifying the source data fits within the destination.

Related Attack Patterns (CAPEC)
CAPEC-8 Buffer Overflow in an API Call
via CWE-120
CAPEC-9 Buffer Overflow in Local Command-Line Utilities
via CWE-120
CAPEC-10 Buffer Overflow via Environment Variables
via CWE-120
CAPEC-14 Client-side Injection-induced Buffer Overflow
via CWE-120
CAPEC-24 Filter Failure through Buffer Overflow
via CWE-120
Show all 13

Mapping is CWE-to-CAPEC per MITRE CAPEC 3.9.

◆ AI Analysis — automated analysis, not human-reviewed

A buffer overflow vulnerability exists in the libtelnet/encrypt.c file of telnetd in FreeBSD versions 7.3 through 9.0, MIT Kerberos Version 5 Applications 1.0.2 and earlier, Heimdal 1.5.1 and earlier, and GNU inetutils. This vulnerability can be exploited by remote attackers to execute arbitrary code via a long encryption key.

BSID: BS-2011-GLOBAL-179097-C • Model: /workspace/models/qwen2.5-coder-32b-instruct-bf16 • Confidence: HIGH

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Frequently Asked Questions
What is CVE-2011-4862?
A buffer overflow vulnerability exists in the libtelnet/encrypt.c file of telnetd in FreeBSD versions 7.3 through 9.0, MIT Kerberos Version 5 Applications 1.0.2 and earlier, Heimdal 1.5.1 and earlier, and GNU inetutils. This vulnerability can be exploited by remote attackers to execute arbitrary code via a long encryption key.
What is the CVSS score for CVE-2011-4862?
CVE-2011-4862 has CVSS 10.0 (Critical). Vector: AV:N/AC:L/Au:N/C:C/I:C/A:C. EPSS: 95.1%.
Is CVE-2011-4862 actively exploited?
Public exploit available for CVE-2011-4862. Exploitation risk elevated.
How do I remediate CVE-2011-4862?
Priority: IMMEDIATE. Advisory: http://lists.freebsd.org/pipermail/freebsd-security/2011-December/006118.html
What systems are affected by CVE-2011-4862?
CVE-2011-4862 affects Debian Debian Linux; Fedoraproject Fedora; Freebsd Freebsd; Gnu Inetutils; Heimdal Project Heimdal; Mit Krb5-Appl; Opensuse Opensuse; Suse Linux Enterprise Software Development Kit, Linux Enterprise Server, Linux Enterprise Desktop.
Vulnerability Details
CVE IDCVE-2011-4862
BSIDBS-2011-GLOBAL-179097-C BreachSpider Global ID
CVSS VectorAV:N/AC:L/Au:N/C:C/I:C/A:C
Published2011-12-25
Last Modified2026-06-16
ICS Relevance15%
Weakness (CWE)
Buffer Copy without Checking Size (Classic Buffer Overflow)
SourceNVD
Official 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.

Source: NIST NVD / MITRE CVE Database

Attack Vector Analysis — CITED Relevance

The vulnerability is triggered by sending a specially crafted long encryption key to the telnetd service. This key overflows a buffer, leading to potential code execution.

Exploitation Likelihood: CRITICAL

Affected Products
VendorProductAffected Versions
Debian Debian Linux 5.0 6.0 7.0
Fedoraproject Fedora 15 16
Freebsd Freebsd ≥ 7.3, ≤ 9.0
Gnu Inetutils < 1.9
Heimdal Project Heimdal ≤ 1.5.1
Mit Krb5-Appl ≤ 1.0.2
Opensuse Opensuse 11.3 11.4
Suse Linux Enterprise Software Development Kit 10 11
Suse Linux Enterprise Server 9 10 11
Suse Linux Enterprise Desktop 10 11
Remediation
View Vendor Advisory →

Remediation Priority: IMMEDIATE

Threat Intelligence
● Threat Intelligence Validated: October 2026 | Threat Age: 5409 Days
CISA known-exploitedNot in KEV catalog
Public Exploit⚠ Available — Reference
PoC CodeNot confirmed
AI Enrichment Record — provenance & audit hash
Model/workspace/models/qwen2.5-coder-32b-instruct-bf16
ConfidenceHIGH
Enriched At2026-05-24
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