CVE-2021-39204

Excessive CPU usage in Pomerium

HIGH

7.5

CVSS Score

Published: September 9, 2021 at 10:10 PM UTC

Updated: June 17, 2026 at 04:03 AM UTC

2 products affected across 2 vendorsEnvoyPomerium

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Severity

HIGH7.5

Exploit prediction

EPSS 2%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Envoy · Envoyproxy

95%

v ≤ 1.16.41.17.0 ≤ v < 1.17.41.18.0 ≤ v < 1.18.41.19.0

Affected range stops below 1.17.4, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.18.4, so it looks safe — our inference, not a vendor statement

Pomerium · Pomerium

95%

v < 0.14.8v < 0.15.10.15.0

Affected range stops below 0.14.8, so it looks safe — our inference, not a vendor statement

Affected range stops below 0.15.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (3)

x_refsource_MISCThird Party Advisory

Source: [email protected]

https://github.com/envoyproxy/envoy/security/advisories/GHSA-3xh3-33v5-chcc

x_refsource_CONFIRMThird Party Advisory

Source: [email protected]

https://github.com/pomerium/pomerium/security/advisories/GHSA-5wjf-62hw-q78r

x_refsource_MISCNot Applicable

Source: [email protected]

https://groups.google.com/g/envoy-announce/c/5xBpsEZZDfE/m/wD05NZBbAgAJ

CVSS

7.5HIGHGitHub_M

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: NONE
Availability: HIGH

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-834

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