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Fencer Vulns
medium 6.5

CVE-2016-3120 json

The validate_as_request function in kdc_util.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.13.6 and 1.4.x be…

published 2016-08-01 10 y ago modified 2026-06-17 4 mo ago also EUVD-2016-4173

cvss
6.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.6%
EPSS 4.6% chance of exploitation in 30 days, percentile 91%
public exploits
0
none known

Summary

The validate_as_request function in kdc_util.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.13.6 and 1.4.x before 1.14.3, when restrict_anonymous_to_tgt is enabled, uses an incorrect client data structure, which allows remote authenticated users to cause a denial of service (NULL pointer dereference and daemon crash) via an S4U2Self request.

Patch / fix

  • krb5 Debian 14, Debian 13, Debian 12 1.14.3+dfsg-1

debian advisories DEBIAN-CVE-2016-3120

  • krb5 Ubuntu 14.04 LTS 1.12+dfsg-2ubuntu5.4
  • krb5 Ubuntu 16.04 LTS 1.13.2+dfsg-5ubuntu2.1

ubuntu advisories UBUNTU-CVE-2016-3120

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • krb5 RHEL 7 1.14.1-26.el7
  • libkadm5 RHEL 7 1.14.1-26.el7
  • krb5-libs RHEL 7 1.14.1-26.el7
  • krb5-pkinit RHEL 7 1.14.1-26.el7
  • krb5-server RHEL 7 1.14.1-26.el7
  • krb5-server-ldap RHEL 7 1.14.1-26.el7
  • krb5-workstation RHEL 7 1.14.1-26.el7

red hat advisories RHSA-2016:2591

  • krb5 SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 +1 more 1.12.1-36.4

suse advisories SUSE-SU-2016:2136-1

  • krb5 openSUSE Tumbleweed 1.15-1.1

opensuse advisories openSUSE-SU-2024:10004-1

  • krb5 Alpine 3.2 1.13.6-r0
  • krb5 Alpine 3.4, Alpine 3.3 1.14.3-r0

alpine advisories ALPINE-CVE-2016-3120

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-3120 updated cvss 5.3

krb5: S4U2Self KDC crash when anon is restricted

  • Red Hat Enterprise Linux 6 krb5, libkadm5, krb5-libs, krb5-server, krb5-server-ldap, krb5-workstation, +1 more
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux Client (v. 7) krb5 1.14.1-26.el7, libkadm5 1.14.1-26.el7, krb5-libs 1.14.1-26.el7, krb5-pkinit 1.14.1-26.el7, krb5-workstation 1.14.1-26.el7 Red Hat Enterprise Linux Client Optional (v. 7) krb5-server 1.14.1-26.el7, krb5-server-ldap 1.14.1-26.el7 Red Hat Enterprise Linux ComputeNode (v. 7) krb5 1.14.1-26.el7, libkadm5 1.14.1-26.el7, krb5-libs 1.14.1-26.el7, krb5-pkinit 1.14.1-26.el7, krb5-workstation 1.14.1-26.el7 Red Hat Enterprise Linux ComputeNode Optional (v. 7) krb5-server 1.14.1-26.el7, krb5-server-ldap 1.14.1-26.el7 Red Hat Enterprise Linux Server (v. 7) krb5 1.14.1-26.el7, libkadm5 1.14.1-26.el7, krb5-libs 1.14.1-26.el7, krb5-pkinit 1.14.1-26.el7, krb5-server 1.14.1-26.el7, krb5-server-ldap 1.14.1-26.el7, +1 more Red Hat Enterprise Linux Workstation (v. 7) krb5 1.14.1-26.el7, libkadm5 1.14.1-26.el7, krb5-libs 1.14.1-26.el7, krb5-pkinit 1.14.1-26.el7, krb5-server 1.14.1-26.el7, krb5-server-ldap 1.14.1-26.el7, +1 more
    fixed: vendor fix RHSA-2016:2591
  • Red Hat Enterprise Linux 5 krb5 Red Hat JBoss Enterprise Application Platform 6 krb5 Red Hat JBoss Enterprise Application Platform 7 krb5 Red Hat JBoss Enterprise Web Server 2 krb5 Red Hat JBoss Enterprise Web Server 3 krb5
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

4.62% chance of exploitation in the next 30 days, higher than 91% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 6.5 CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:N/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.