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.
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.012 (68.5th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 68th percentile — 68.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000
Affected products
- Envoyproxy Envoy — versions >= 1.19.0, < 1.19.1, >= 1.18.0, < 1.18.4, 1.19.0
Weakness classification (CWE)
References
- www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history (Vendor Advisory)
- github.com/envoyproxy/envoy/security/advisories/GHSA-j374-mjrw-vvp8 (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.