Vulnerability Note VU#623332

MIT Kerberos 5 contains double free vulnerability in "krb5_recvauth()" function

Original Release date: 13 Jul 2005 | Last revised: 08 Aug 2005


An unauthenticated attacker can cause krb5_recvauth() function to free a block of memory twice, possibly leading to arbitrary code execution.


Kerberos is a network authentication system that uses a trusted third party (a KDC) to authenticate clients and servers to each other. It is designed to provide strong authentication for client/server applications by using secret-key cryptography. MIT Kerberos code is used in network applications from a variety of different vendors and is included in many UNIX and Linux distributions.

MIT krb5 Security Advisory 2005-003 issued 2005 July 12, available from
<> states:

    The krb5_recvauth() function can free previously freed memory under some error conditions. This vulnerability may allow an unauthenticated remote attacker to execute arbitrary code. Exploitation of this vulnerability on a Kerberos Key Distribution Center (KDC) host can result in compromise of an entire Kerberos realm. No exploit code is known to exist at this time. Exploitation of double-free vulnerabilities is believed to be difficult.


An unauthenticated attacker may be able to execute arbitrary code in the context of a program calling krb5_recvauth(). This includes the kpropd program which typically runs on slave Key Distribution Center (KDC) hosts, potentially leading to compromise of an entire Kerberos realm. For more information please see the MIT krb5 Security Advisory 2005-003.


Apply patches available from your vendor. Details of the patch are also available from

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
MiT Kerberos Development TeamAffected-12 Jul 2005
Red Hat Inc.Affected06 Jun 200512 Jul 2005
Sun Microsystems Inc.Affected06 Jun 200513 Jul 2005
Check PointNot Affected06 Jun 200509 Jun 2005
F5 NetworksNot Affected06 Jun 200506 Jun 2005
Force10 Networks Inc.Not Affected06 Jun 200507 Jun 2005
HitachiNot Affected10 May 200512 Jul 2005
Juniper NetworksNot Affected06 Jun 200512 Jul 2005
Microsoft CorporationNot Affected06 Jun 200506 Jun 2005
NetfilterNot Affected06 Jun 200509 Jun 2005
WatchGuardNot Affected06 Jun 200512 Jul 2005
Apple Computer Inc.Unknown06 Jun 200512 Jul 2005
ConnectivaUnknown06 Jun 200512 Jul 2005
Cray Inc.Unknown06 Jun 200512 Jul 2005
DebianUnknown06 Jun 200512 Jul 2005
If you are a vendor and your product is affected, let us know.View More »

CVSS Metrics (Learn More)

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



This vulnerability was reported by the MIT Kerberos Development Team. The MIT Kerberos Development Team thanks Magnus Hagander for reporting this vulnerability.

This document was written by Robert Mead based on information in the MIT krb5 Security Advisory 2005-003.

Other Information

  • CVE IDs: CAN-2005-1689
  • Date Public: 12 Jul 2005
  • Date First Published: 13 Jul 2005
  • Date Last Updated: 08 Aug 2005
  • Severity Metric: 13.01
  • Document Revision: 19


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