Description
In Heimdal through 7.4, remote unauthenticated attackers are able to crash the KDC by sending a crafted UDP packet containing empty data fields for client name or realm. The parser would unconditionally dereference NULL pointers in that case, leading to a segmentation fault. This is related to the _kdc_as_rep function in kdc/kerberos5.c and the der_length_visible_string function in lib/asn1/der_length.c.
References (7)
Core 7
Core References
Issue Tracking, Mailing List, Third Party Advisory x_refsource_confirm
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878144
Third Party Advisory x_refsource_confirm
https://github.com/heimdal/heimdal/commit/1a6a6e462dc2ac6111f9e02c6852ddec4849b887
Various Sources x_refsource_confirm
http://www.h5l.org/pipermail/heimdal-announce/2017-December/000008.html
Third Party Advisory x_refsource_misc
http://www.h5l.org/pipermail/heimdal-discuss/2017-August/000259.html
Patch, Third Party Advisory x_refsource_confirm
https://github.com/heimdal/heimdal/issues/353
Various Sources x_refsource_confirm
http://h5l.org/advisories.html?show=2017-12-08
Third Party Advisory vendor-advisory
x_refsource_debian
https://www.debian.org/security/2017/dsa-4055
Scores
CVSS v3
7.5
EPSS
0.0399
EPSS Percentile
88.5%
Attack Vector
NETWORK
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Details
CWE
CWE-476
Status
published
Products (2)
debian/debian_linux
9.0
heimdal_project/heimdal
< 7.4.0
Published
Dec 06, 2017
Tracked Since
Feb 18, 2026