CVE-2016-3120

Severity: medium (CVSS 6.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 4.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2016-08-01 · updated 2026-06-17
Weakness: CWE-476

Description

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.

Affected products

MIT Kerberos 5: 1.13, 1.13.1, 1.13.2, 1.13.3, 1.13.4, 1.13.5 (+4)

References

http://krbdev.mit.edu/rt/Ticket/Display.html?id=8458
http://lists.opensuse.org/opensuse-updates/2016-09/msg00035.html
http://rhn.redhat.com/errata/RHSA-2016-2591.html
http://web.mit.edu/kerberos/krb5-1.13/
http://web.mit.edu/kerberos/krb5-1.14/
http://www.securityfocus.com/bid/92132
http://www.securitytracker.com/id/1036442
https://github.com/krb5/krb5/commit/93b4a6306a0026cf1cc31ac4bd8a49ba5d034ba7
https://lists.debian.org/debian-lts-announce/2018/01/msg00040.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AWL3KYFRJIX37EAM4DKCQQIQP2WBKL35/
http://krbdev.mit.edu/rt/Ticket/Display.html?id=8458
http://lists.opensuse.org/opensuse-updates/2016-09/msg00035.html

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