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NVD / CVE Program· CNA freebsd

CVE-2011-4862: 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…

CriticalCVSS 10.0 · v2.0—Weaponized Fix available

Noroxi assessment

Priority: This week (action score 69/100)

  • A ready-made attack module is public (Metasploit); exploiting it takes no special expertise.
  • Public proof-of-concept code exists (Exploit-DB, GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 95% (FIRST EPSS); higher than 99.8% of all records.
  • No special conditions are required; it is repeatable.
  • Fixed version: heimdal (Debian:12) 1.5.dfsg.1-1; inetutils (Debian:12) 2:1.8-6; krb5 (Debian:12) 1.8+dfsg~aa+r23527-1.

Don’t wait for the next maintenance window. Upgrade to heimdal (Debian:12) 1.5.dfsg.1-1; inetutils (Debian:12) 2:1.8-6; krb5 (Debian:12) 1.8+dfsg~aa+r23527-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Dec 24, 2011
Updated
Jun 16, 2026
EPSS
95.0% · 99th percentile

Report tools

JSON

Action score

69

This week

Don’t wait for the next maintenance window.

CVSS
40 / 40 · 10.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
29 / 30 · 95.0%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Weaponized exploit exists
  • A fix has been released

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Follow CVE-2011-4862

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  • when exploit code appears or is weaponized
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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
mitkrb5-appl
gnuinetutils
heimdal projectheimdal
freebsdfreebsd
fedoraprojectfedora
debiandebian linux
opensuseopensuse
suselinux enterprise desktop
suselinux enterprise server
suselinux enterprise software development kit

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux5.0
  • debian debian linux6.0
  • debian debian linux7.0
  • fedoraproject fedora15
  • fedoraproject fedora16
  • freebsd freebsd7.3 and later · up to 9.0 inclusive
  • gnu inetutilsbefore 1.9
  • heimdal project heimdalup to 1.5.1 inclusive
+10 more rows
  • mit krb5-applup to 1.0.2 inclusive
  • opensuse opensuse11.3
  • opensuse opensuse11.4
  • suse linux enterprise desktop10
  • suse linux enterprise desktop11
  • suse linux enterprise server10
  • suse linux enterprise server11
  • suse linux enterprise server9
  • suse linux enterprise software development kit10
  • suse linux enterprise software development kit11

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12heimdalbefore 1.5.dfsg.1-11.5.dfsg.1-1
Debian:12inetutilsbefore 2:1.8-62:1.8-6
Debian:12krb5before 1.8+dfsg~aa+r23527-11.8+dfsg~aa+r23527-1
Debian:5.0heimdalbefore 1.2.dfsg.1-2.1+lenny11.2.dfsg.1-2.1+lenny1
Debian:5.0inetutilsbefore 2:1.5.dfsg.1-9+lenny12:1.5.dfsg.1-9+lenny1
Debian:5.0krb5before 1.6.dfsg.4~beta1-5lenny71.6.dfsg.4~beta1-5lenny7
Debian:6.0heimdalbefore 1.4.0~git20100726.dfsg.1-2+squeeze11.4.0~git20100726.dfsg.1-2+squeeze1
Debian:6.0inetutilsbefore 2:1.6-3.1+squeeze12:1.6-3.1+squeeze1
Debian:6.0krb5-applbefore 1:1.0.1-1.21:1.0.1-1.2
Red Hat:enterprise_linux:4::askrb5before 0:1.3.4-65.el40:1.3.4-65.el4
Red Hat:enterprise_linux:4::askrb5-debuginfobefore 0:1.3.4-65.el40:1.3.4-65.el4
Red Hat:enterprise_linux:4::askrb5-develbefore 0:1.3.4-65.el40:1.3.4-65.el4
Red Hat:enterprise_linux:4::askrb5-libsbefore 0:1.3.4-65.el40:1.3.4-65.el4
Red Hat:enterprise_linux:4::askrb5-serverbefore 0:1.3.4-65.el40:1.3.4-65.el4
Red Hat:enterprise_linux:4::askrb5-workstationbefore 0:1.3.4-65.el40:1.3.4-65.el4
Red Hat:enterprise_linux:5::clientkrb5before 0:1.6.1-63.el5_70:1.6.1-63.el5_7
Red Hat:enterprise_linux:5::clientkrb5-debuginfobefore 0:1.6.1-63.el5_70:1.6.1-63.el5_7
Red Hat:enterprise_linux:5::clientkrb5-libsbefore 0:1.6.1-63.el5_70:1.6.1-63.el5_7
Red Hat:enterprise_linux:5::clientkrb5-workstationbefore 0:1.6.1-63.el5_70:1.6.1-63.el5_7
Red Hat:enterprise_linux:5::client_workstationkrb5-develbefore 0:1.6.1-63.el5_70:1.6.1-63.el5_7
Red Hat:enterprise_linux:5::client_workstationkrb5-serverbefore 0:1.6.1-63.el5_70:1.6.1-63.el5_7
Red Hat:enterprise_linux:5::client_workstationkrb5-server-ldapbefore 0:1.6.1-63.el5_70:1.6.1-63.el5_7
Red Hat:enterprise_linux:6::clientkrb5-applbefore 0:1.0.1-7.el6_20:1.0.1-7.el6_2
Red Hat:enterprise_linux:6::clientkrb5-appl-clientsbefore 0:1.0.1-7.el6_20:1.0.1-7.el6_2

+29

Same product

mit: all records

Other highest-scoring records for the same primary product.

  • CVE-2019-25018In the rcp client in MIT krb5-appl through 1.0.3, malicious servers could bypass intended access restrictions via the filename of .
    30Monitor
  • CVE-2011-1526ftpd.c in the GSS-API FTP daemon in MIT Kerberos Version 5 Applications (aka krb5-appl) 1.0.1 and earlier does not check the krb5_setegid…
    27Monitor
  • CVE-2019-25017An issue was discovered in rcp in MIT krb5-appl through 1.0.3.
    23Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:heimdal1.5.dfsg.1-1 · Debian:12Package registry (OSV)
debian:inetutils2:1.8-6 · Debian:12Package registry (OSV)
debian:krb51.8+dfsg~aa+r23527-1 · Debian:12Package registry (OSV)
debian:krb5-appl1:1.0.1-1.2 · Debian:6.0Package registry (OSV)
red hat:krb50:1.3.4-65.el4 · Red Hat:enterprise_linux:4::asPackage registry (OSV)
red hat:krb5-appl0:1.0.1-7.el6_2 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
red hat:krb5-appl-clients0:1.0.1-7.el6_2 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
red hat:krb5-appl-debuginfo0:1.0.1-7.el6_2 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
red hat:krb5-appl-servers0:1.0.1-7.el6_2 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
red hat:krb5-debuginfo0:1.3.4-65.el4 · Red Hat:enterprise_linux:4::asPackage registry (OSV)
red hat:krb5-devel0:1.3.4-65.el4 · Red Hat:enterprise_linux:4::asPackage registry (OSV)
red hat:krb5-libs0:1.3.4-65.el4 · Red Hat:enterprise_linux:4::asPackage registry (OSV)
red hat:krb5-server0:1.3.4-65.el4 · Red Hat:enterprise_linux:4::asPackage registry (OSV)
red hat:krb5-server-ldap0:1.6.1-63.el5_7 · Red Hat:enterprise_linux:5::client_workstationPackage registry (OSV)
red hat:krb5-workstation0:1.3.4-65.el4 · Red Hat:enterprise_linux:4::asPackage registry (OSV)

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Metasploit module ×3
  • Exploit-DB entry ×3
  • Proof-of-concept repository on GitHub ×3

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHub3 repositories2017-02-02 → 2020-02-06
Exploit-DB entryremote2012-01-14
Exploit-DB entryremote2012-01-14
Exploit-DB entryremote2011-12-26
Metasploit moduleauxiliary/scanner/telnet/telnet_encrypt_overflowTelnet Service Encryption Key ID Overflow Detectionauxiliary—
Metasploit moduleexploit/freebsd/telnet/telnet_encrypt_keyidFreeBSD Telnet Service Encryption Key ID Buffer Overflowexploit2011-12-23
Metasploit moduleexploit/linux/telnet/telnet_encrypt_keyidLinux BSD-derived Telnet Service Encryption Key ID Buffer Overflowexploit2011-12-23

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Metasploit-2 d
  2. Published
  3. First PoC+1 d
  4. TodayNov 13, 2026+5438 d

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Not on record for this CVE: EPSS history · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • No special conditions are required; it is repeatable.

If successful

Confidentiality
C · data can be read
Integrity
C · data or configuration can be modified
Availability
C · the service can be disrupted
Attack complexity
Low
Confidentiality impact
C
Integrity impact
C
Availability impact
C

Weakness class (CWE)

CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CVSS vector

AV:N/AC:L/Au:N/C:C/I:C/A:C

nvd-primary

Root cause

When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.

The bug in code

The whole CWE-120 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
char buf[256];memcpy(buf, pkt->data, pkt->len);

Fixed

c
char buf[256];if (pkt->len > sizeof(buf)) {  return -EINVAL;}memcpy(buf, pkt->data, pkt->len);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (19 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records