CVE-2018-5733: A malicious client can overflow a reference counter in ISC dhcpd
Document version: 2.0
Posting date: 28 February 2018
Program impacted: ISC DHCP
Versions affected: 4.1.0 -> 4.1-ESV-R15, 4.2.0 -> 4.2.8, 4.3.0 -> 4.3.6, 4.4.0
A malicious client which is allowed to send very large amounts of traffic (billions of packets) to a DHCP server can eventually overflow a 32-bit reference counter, potentially causing dhcpd to crash.
Successful exploitation of this vulnerability may exhaust the memory available to dhcpd and/or cause it to crash, resulting in a denial of service to clients.
CVSS Score: 5.9
CVSS Vector: CVSS:3.0/AV:N/AC:H/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:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
Active exploits: No known active exploits.
Solution: Upgrade to the patched release most closely related to your current version of DHCP. These are all available at https://www.isc.org/downloads.
- DHCP 4.1-ESV-R15-P1
- DHCP 4.3.6-P1
- DHCP 4.4.1
Acknowledgements: ISC would like to thank Felix Wilhelm, Google Security Team, for reporting this vulnerability.
Document Revision History:
1.0 Advance Notification, 21 February 2018
2.0 Public Disclosure, 28 February 2018
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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/.)
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