Vulnerability Description
Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions envoy’s procedure for resetting a HTTP/2 stream has O(N^2) complexity, leading to high CPU utilization when a large number of streams are reset. Deployments are susceptible to Denial of Service when Envoy is configured with high limit on H/2 concurrent streams. An attacker wishing to exploit this vulnerability would require a client opening and closing a large number of H/2 streams. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes to reduce time complexity of resetting HTTP/2 streams. As a workaround users may limit the number of simultaneous HTTP/2 dreams for upstream and downstream peers to a low number, i.e. 100.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Envoyproxy | Envoy | >= 1.16.0, < 1.16.5 |
Related Weaknesses (CWE)
References
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-3xh3-33v5-chccThird Party Advisory
- https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_historyRelease NotesVendor Advisory
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-3xh3-33v5-chccThird Party Advisory
- https://www.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_historyRelease NotesVendor Advisory
FAQ
What is CVE-2021-32778?
CVE-2021-32778 is a vulnerability with a CVSS score of 5.8 (MEDIUM). Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions envoy’s procedure for resetting a HTTP/2 stream has O(N^2) complex...
How severe is CVE-2021-32778?
CVE-2021-32778 has been rated MEDIUM with a CVSS base score of 5.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-32778?
Check the references section above for vendor advisories and patch information. Affected products include: Envoyproxy Envoy.