CVE-2021-32780

Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions Envoy transitions a H/2 connection to the CLOSED state when it receives a GOAWAY frame without any streams outstanding. The connection state is transitioned to DRAINING when it receives a SETTING frame with the SETTINGS_MAX_CONCURRENT_STREAMS parameter set to 0. Receiving these two frames in the same I/O event results in abnormal termination of the Envoy process due to invalid state transition from CLOSED to DRAINING. A sequence of H/2 frames delivered by an untrusted upstream server will result in Denial of Service in the presence of untrusted **upstream** servers. Envoy versions 1.19.1, 1.18.4 contain fixes to stop processing of pending H/2 frames after connection transition to the CLOSED state.

• CWE-754
• CWE-754

• https://github.com/envoyproxy/envoy/security/advisories/GHSA-j374-mjrw-vvp8Third Party Advisory
• https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_historyVendor Advisory
• https://github.com/envoyproxy/envoy/security/advisories/GHSA-j374-mjrw-vvp8Third Party Advisory
• https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_historyVendor Advisory

Published

Aug 24, 2021

Last Modified

Jun 17, 2026

Status

Modified

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