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CVE-2021-32778

5.8 · MEDIUM

Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures.

Published Aug 24, 2021CWE-834EPSS 1.23%

Overview

CVE-2021-32778 is a medium-severity vulnerability. It was published on August 24, 2021 and has a CVSS 3.1 base score of 5.8 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.8, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubgithub.com/envoyproxy/envoy/security/advisories/GHSA-3xh3-33v5-chccRefwww.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_historyGitHubgithub.com/envoyproxy/envoy/security/advisories/GHSA-3xh3-33v5-chccRefwww.envoyproxy.io/docs/envoy/v1.19.0/version_history/version_history

How CyberStrike helps

Frequently asked questions

What is CVE-2021-32778?

CVE-2021-32778 is a medium-severity vulnerability. It was published on August 24, 2021 and has a CVSS 3.1 base score of 5.8 (MEDIUM).

How severe is CVE-2021-32778?

This vulnerability has a CVSS 3.1 base score of 5.8, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-32778?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-32778?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-32778 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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