CVE-2021-39162: Envoyproxy Envoy

High severity, CVSS 8.6. EPSS: 1.6% chance of exploitation in the next 30 days.

Pomerium is an open source identity-aware access proxy. Envoy, which Pomerium is based on, can abnormally terminate if an H/2 GOAWAY and SETTINGS frame are received in the same IO event. This can lead to a DoS in the presence of untrusted *upstream* servers. 0.15.1 contains an upgraded envoy binary with this vulnerability patched. If only trusted upstreams are configured, there is not substantial risk of this condition being triggered.

Affected products

• Envoyproxy Envoy: before 1.18.4 (fixed in 1.18.4); version 1.19.0 only
• Pomerium Pomerium: version 0.15.0 only

Published 2021-09-09. Last modified 2026-06-17.