[Kea-announce] CVE-2019-6473: An invalid hostname option can cause the kea-dhcp4 server to terminate

Michael McNally mcnally at isc.org
Wed Aug 28 21:08:49 UTC 2019

CVE:                 CVE-2019-6473
Document Version:    2.0
Posting date:        28 August 2019
Program Impacted:    Kea DHCP
Versions affected:   1.4.0 -> 1.5.0. Versions prior to 1.4.0 are
                     considered "End of Life" and have not been tested
                     for this vulnerability, though they are believed to
                     be affected. Also affects development versions
                     and 1.6.0-beta2
Severity:            Medium


   From adjacent networks permitted to relay DHCP traffic to the
   Kea server


   An invalid hostname option can trigger an assertion failure in
   the Kea DHCPv4 server process (kea-dhcp4), causing the server
   process to exit.


   An attacker who is able to deliberately exploit this vulnerability
   can cause the kea-dhcp4 server to stop executing, resulting in
   denial of service to clients.

   Only the DHCPv4 service is affected by this vulnerability.

CVSS Score:          6.5
CVSS Vector:         CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

For more information on the Common Vulnerability Scoring System and
to obtain your specific environmental score please visit:



Active exploits:

   No known active exploits


   Upgrade to a version of Kea containing a fix, available via

   -  Kea 1.4.0-P2
   -  Kea 1.5.0-P1
   -  Kea 1.6.0

Document Revision History:

   1.0 Advance Notification, 21 August 2019
   2.0 Public Disclosure, 28 August 2019

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   versions are actively supported, please see

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