CVE-2021-39204: Excessive CPU usage in github.com/pomerium/pomerium
Summary
CVE-2021-39204: Excessive CPU usage. Affects github.com/pomerium/pomerium across 2 version ranges.
< 0.14.8
>= 0.15.0, < 0.15.1
Fixed in 0.14.8 or 0.15.1, depending on the release line you run. How to fix ↓
Also tracked for
- envoy · Bitnami
The same CVE-2021-39204 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
github.com/pomerium/pomerium is an open-source package written in Go that is used for building secure access proxies. It is based on Envoy, a popular proxy server. The package provides features like single sign-on, access control, and secure remote access to internal applications. However, it is vulnerable to an issue related to the handling of HTTP/2 streams in Envoy, which can result in excessive CPU usage.
Vulnerability Detail
The vulnerability arises from the incorrect handling of resetting HTTP/2 streams with excessive complexity in Envoy, which Pomerium is based on. When a large number of streams are reset, it can lead to high CPU utilization, causing a Denial of Service (DoS) condition. This means that an attacker could exploit this vulnerability to overload the server and make it unresponsive.
How To Fix
Latest published version: v0.33.4 as of 22 Oct 2026
go get github.com/pomerium/pomerium@v0.33.4Upgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.
If you can't move to the latest
The minimum fixed version depends on the release line you run.
-
< 0.14.80.14.8go get github.com/pomerium/pomerium@v0.14.8 -
>= 0.15.0, < 0.15.10.15.1go get github.com/pomerium/pomerium@v0.15.1
Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →
Conclusion
The vulnerability in github.com/pomerium/pomerium can lead to excessive CPU usage and a Denial of Service (DoS) condition. To mitigate this vulnerability, it is crucial to upgrade to Pomerium versions 0.14.8 or 0.15.1, which contain the necessary patches. For further support on vulnerability remediation, you can reach out to the Pomerium team at security@pomerium.com.
See every vulnerability recorded for github.com/pomerium/pomerium →
FAQ
The vulnerability can result in a Denial of Service (DoS) condition, causing the server to become unresponsive.
You can mitigate this vulnerability by upgrading to Pomerium versions 0.14.8 or 0.15.1, which contain the patched vulnerability.
No, there are no known workarounds for this vulnerability. Upgrading to the patched versions is the recommended solution.
Yes, you can find more information about this vulnerability in the Envoy security advisory GHSA-3xh3-33v5-chcc and the CVE entry CVE-2021-32778.
If you have any questions or comments about this advisory, you can open an issue in the pomerium/pomerium GitHub repository or email the Pomerium team at security@pomerium.com.
References
Related vulnerabilities
Recent vulnerabilities recorded for github.com/pomerium/pomerium.
