CVE-2019-6473: An invalid hostname option can cause the kea-dhcp4 server to terminate
  • 28 Aug 2019
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CVE-2019-6473: An invalid hostname option can cause the kea-dhcp4 server to terminate

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Article summary

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 1.6.0-beta1 and 1.6.0-beta2

Severity: Medium

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

Description:

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

Impact:

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: https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Workarounds:

None.

Active exploits:

No known active exploits

Solution:

Upgrade to a version of Kea containing a fix, available via https://www.isc.org/downloads.

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

Acknowledgements:

Document Revision History:

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

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Note: ISC patches only currently supported versions. When possible we indicate EOL versions affected. (For current information on which versions are actively supported, please see https://www.isc.org/downloads/).

ISC Security Vulnerability Disclosure Policy: Details of our current security advisory policy and practice can be found in the ISC Software Defect and Security Vulnerability Disclosure Policy.

This Knowledgebase article is the complete and official security advisory document.

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