Denial of service.

Nov 7, 2019

Disclosure Details
CVSS Impact Score7.5 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:H/RL:O/RC:C
Affected Releases1.3 to 1.3.4

Envoy, and subsequently Istio, are vulnerable to the following DoS attack. An infinite loop can be triggered in Envoy if the option continue_on_listener_filters_timeout is set to True. This has been the case for Istio since the introduction of the Protocol Detection feature in Istio 1.3 A remote attacker may trivially trigger that vulnerability, effectively exhausting Envoy’s CPU resources and causing a denial-of-service attack.

Impact and detection

Both Istio gateways and sidecars are vulnerable to this issue. If you are running one of the affected releases, your cluster is vulnerable.


Reporting vulnerabilities

We’d like to remind our community to follow the vulnerability reporting process to report any bug that can result in a security vulnerability.