Vulnerability in Envoyproxy Envoy
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.
EPSS: 0.012 (66.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.
Affected products
- Envoyproxy Envoy — versions >= 1.19.0, < 1.19.1, >= 1.18.0, < 1.18.4, 1.19.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_MISC, Vendor Advisory)
- security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-32780?
- CVE-2021-32780 is a high-severity vulnerability in Envoyproxy Envoy, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 8.6/10. Published 2021-08-24.
- How severe is CVE-2021-32780?
- High severity. CVSS v3 base score is 8.6 out of 10.