CVE-2018-5739

Failure to release memory may exhaust system resources

Published Jan 16, 2019 CVSS 3.0 · 6.5 Medium EPSS 1.9% KEV · Not listed
Description
An extension to hooks capabilities which debuted in Kea 1.4.0 introduced a memory leak for operators who are using certain hooks library facilities. In order to support multiple requests simultaneously, Kea 1.4 added a callout handle store but unfortunately the initial implementation of this store does not properly free memory in every case. Hooks which make use of query4 or query6 parameters in their callouts can leak memory, resulting in the eventual exhaustion of available memory and subsequent failure of the server process. Affects Kea DHCP 1.4.0.

Remediation

Vendor Solution

Upgrade to Kea 1.4.0-P1 or higher, available via https://www.isc.org/downloads.


Vendor Workaround

+ Monitoring and routinely restarting ISC Kea DHCPv4 and DHCPv6 services may be an effective mitigation for some production environments + Running a new build of Kea without any hook libraries that use the callout store is another option, though it may not be a viable option where the production environment is dependent on the other hooks that need to be omitted to avoid these symptoms. These hooks distributed by ISC do not use the callout store and are safe to use: Lease Commands, Stat Commands, Host Commands (a Kea Premium hook) and Subnet Commands (a subscriber-only hook provided to Kea support customers). + Reverting to Kea DHCP 1.3.0 may be possible for some production environments but because of differences in the database schema operators should check carefully before attempting rollback: - If using memfile storage entirely, there should not be any compatibility issues. - If using a database solution for hosts or leases, the 1.4.0 schema will be incompatible with ISC Kea 1.3.0; the database therefore must be restored from a pre-upgrade backup for this to be successful. - If you are unsure whether or not you can roll back to 1.3.0 without restoring a previous version of your database, you may send an e-mail to security-officer@isc.org describing your storage setup and we will advise.

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2018-17508 An extension to hooks capabilities which debuted in Kea 1.4.0 introduced a memory leak for operators who are using certain hooks library facilities. In order to support multiple requests simultaneously, Kea 1.4 added a callout handle store but unfortunately the initial implementation of this store does not properly free memory in every case. Hooks which make use of query4 or query6 parameters in their callouts can leak memory, resulting in the eventual exhaustion of available memory and subsequent failure of the server process. Affects Kea DHCP 1.4.0.
References
History

No history.

Weaknesses

Sources

Status
PUBLISHED
Assigner
isc
Published
Updated
Sep 17, 2024, 2:11 AM
Reserved
Jan 17, 2018, 12:00 AM
Status
Modified
Published
Jan 16, 2019, 8:29 PM
Modified
Jun 17, 2026, 2:00 AM