==================================================================== OSSA-2021-005: Arbitrary dnsmasq reconfiguration via extra_dhcp_opts ====================================================================

:Date: August 31, 2021 :CVE: CVE-2021-40085

Affects ~~~~~~~ - Neutron: <16.4.1, >=17.0.0 <17.2.1, >=18.0.0 <18.1.1

Description ~~~~~~~~~~~ Pavel Toporkov reported a vulnerability in Neutron. By supplying a specially crafted extra_dhcp_opts value, an authenticated user may add arbitrary configuration to the dnsmasq process in order to crash the service, change parameters for other tenants sharing the same interface, or otherwise alter that daemon's behavior. This vulnerability may also be used to trigger a configuration parsing buffer overflow in versions of dnsmasq prior to 2.81, which could lead to remote code execution. All Neutron deployments are affected.

Patches ~~~~~~~ - https://review.opendev.org/806750 (Ussuri) - https://review.opendev.org/806749 (Victoria) - https://review.opendev.org/806748 (Wallaby) - https://review.opendev.org/806746 (Xena)

Credits ~~~~~~~ - Pavel Toporkov (CVE-2021-40085)

References ~~~~~~~~~~ - https://launchpad.net/bugs/1939733 - http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-40085