HOMEVULNERABILITIESCVE-2017-17439
HIGH

CVE-2017-17439

CWE-476Published: December 6, 2017· Updated: Jun 17, 2026

7.5
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2017-17439 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

Debian1 product(s)
debian linux
heimdal_project1 product(s)
heimdal
Source: NVD CPE · 2 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/heimdal/heimdal/issues/353
PATCHhttps://github.com/heimdal/heimdal/issues/353
ADVISORYhttp://www.h5l.org/pipermail/heimdal-discuss/2017-August/000259.html
ADVISORYhttps://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878144
ADVISORYhttps://github.com/heimdal/heimdal/commit/1a6a6e462dc2ac6111f9e02c6852ddec4849b887
ADVISORYhttps://www.debian.org/security/2017/dsa-4055
ADVISORYhttp://www.h5l.org/pipermail/heimdal-discuss/2017-August/000259.html
ADVISORYhttps://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878144
ADVISORYhttps://github.com/heimdal/heimdal/commit/1a6a6e462dc2ac6111f9e02c6852ddec4849b887
ADVISORYhttps://www.debian.org/security/2017/dsa-4055

All References (14)

→
http://h5l.org/advisories.html?show=2017-12-08
→
http://www.h5l.org/pipermail/heimdal-announce/2017-December/000008.html
→
http://www.h5l.org/pipermail/heimdal-discuss/2017-August/000259.htmlThird Party Advisory
→
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878144Issue Tracking · Mailing List · Third Party Advisory
→
https://github.com/heimdal/heimdal/commit/1a6a6e462dc2ac6111f9e02c6852ddec4849b887Third Party Advisory
→
https://github.com/heimdal/heimdal/issues/353Patch · Third Party Advisory
→
https://www.debian.org/security/2017/dsa-4055Third Party Advisory
→
http://h5l.org/advisories.html?show=2017-12-08
→
http://www.h5l.org/pipermail/heimdal-announce/2017-December/000008.html
→
http://www.h5l.org/pipermail/heimdal-discuss/2017-August/000259.htmlThird Party Advisory
→
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878144Issue Tracking · Mailing List · Third Party Advisory
→
https://github.com/heimdal/heimdal/commit/1a6a6e462dc2ac6111f9e02c6852ddec4849b887Third Party Advisory
→
https://github.com/heimdal/heimdal/issues/353Patch · Third Party Advisory
→
https://www.debian.org/security/2017/dsa-4055Third Party Advisory

Quick Facts

CVE IDCVE-2017-17439
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-476
CISA KEVNo
Affected2 vendor(s)
PublishedDec 6, 2017

Related CVEs (CWE-476)

CVE-2010-2495
10.0
CVE-2022-36648
10.0
CVE-2020-5544
9.8
CVE-2019-17539
9.8
CVE-2019-18190
9.8
CVE-2019-16092
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2017-17439 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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