CVE-2021-32780
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.23%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 1.23% probability · 67th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-754
- Affected
- envoyproxy/envoy
- Source
- security-advisories@github.com
References
- 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
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.