CVE-2017-17439

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.

Category

7.5
CVSS
Severity: High
CVSS 3.0 •
CVSS 2.0 •
EPSS 9.13% Top 10%
Vendor Advisory debian.org
Affected: n/a n/a
Published at:
Updated at:

References

Link Tags
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878144 mailing list third party advisory issue tracking
https://github.com/heimdal/heimdal/commit/1a6a6e462dc2ac6111f9e02c6852ddec4849b887 third party advisory
http://www.h5l.org/pipermail/heimdal-announce/2017-December/000008.html
http://www.h5l.org/pipermail/heimdal-discuss/2017-August/000259.html third party advisory
https://github.com/heimdal/heimdal/issues/353 third party advisory patch
http://h5l.org/advisories.html?show=2017-12-08
https://www.debian.org/security/2017/dsa-4055 third party advisory vendor advisory

Frequently Asked Questions

What is the severity of CVE-2017-17439?
CVE-2017-17439 has been scored as a high severity vulnerability.
How to fix CVE-2017-17439?
To fix CVE-2017-17439, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2017-17439 being actively exploited in the wild?
It is possible that CVE-2017-17439 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~9% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
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