Vulnerability Note VU#541921

ISC DHCP server fails to handle zero-length client identifier

Original Release date: 14 Jul 2010 | Last revised: 14 Jul 2010


A vulnerability in ISC DHCP could allow a remote attacker to cause the DHCP server to exit, resulting in a denial of service.


ISC DHCP is a commonly redistributed reference implementation of the Dynamic Host Configuration Protocol (DHCP), including a server, client, and relay agent. The server component contains a fencepost error in the way that it handles client identifiers. As a result, a request from a client system containing a zero-length client id will cause the server to exit.

ISC indicates that this vulnerability affects ISC-DHCP versions 4.0.x, 4.1.x, and 4.2.x but not 3.1.x. We are aware of publicly available exploit code for this vulnerability.


A remote unauthenticated attacker may cause the DHCP server to exit, thereby causing a denial of service.


Upgrade or apply a patch from the vendor

Patches and updated versions of the software have been released to address this issue. Please see the Systems Affected section of this document for more information.

Users who compile their DHCP software from the original source distribution should upgrade to one of the following versions: 4.1.1-P1 or 4.0.2-P1.

Vendor Information (Learn More)

VendorStatusDate NotifiedDate Updated
Fedora ProjectAffected-14 Jul 2010
Internet Systems ConsortiumAffected-14 Jul 2010
Mandriva S. A.Affected-14 Jul 2010
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A



Thanks to ISC for reporting this vulnerability.

This document was written by Chad R Dougherty.

Other Information

  • CVE IDs: CVE-2010-2156
  • Date Public: 01 Jun 2010
  • Date First Published: 14 Jul 2010
  • Date Last Updated: 14 Jul 2010
  • Severity Metric: 5.62
  • Document Revision: 7


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