krb5: Denial of service - Remote/unauthenticated

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                         ZMCIRT Vulnerability Bulletin

                             ZMC-2021.07.26.0900
            krb5: Denial of service - Remote/unauthenticated
                               26th July 2021

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Product:           krb5
Publisher:         Debian
Operating System:  Debian GNU/Linux
                   UNIX variants (UNIX, Linux, OSX)
                   Windows
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-36222  

Original Bulletin: 
   http://www.debian.org/security/2021/dsa-4944

Comment: This advisory references vulnerabilities in products which run on 
         platforms other than Debian. It is recommended that administrators 
         running krb5 check for an updated version of the software for their
         operating system.

Package        : krb5
CVE ID         : CVE-2021-36222
Debian Bug     : 991365

It was discovered that the Key Distribution Center (KDC) in krb5, the
MIT implementation of Kerberos, is prone to a NULL pointer dereference
flaw. An unauthenticated attacker can take advantage of this flaw to
cause a denial of service (KDC crash) by sending a request containing a
PA-ENCRYPTED-CHALLENGE padata element without using FAST.

For the stable distribution (buster), this problem has been fixed in
version 1.17-3+deb10u2.

We recommend that you upgrade your krb5 packages.

For the detailed security status of krb5 please refer to its security
tracker page at:
https://security-tracker.debian.org/tracker/krb5


 
ZMCIRT has made every effort to ensure that the information contained
in this document is accurate.  However, the decision to use the information
described is the responsibility of each user or organisation. The decision to
follow or act on information or advice contained in this security bulletin is
the responsibility of each user or organisation, and should be considered in
accordance with your organisation's site policies and procedures. ZMCERT
takes no responsibility for consequences which may arise from following or
acting on information or advice contained in this security bulletin.

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