What’s Vulnerable › Vulnerabilities

CVE-2021-39206: Incorrect Authorization with specially crafted requests

• Severity: high (CVSS 8.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-09-09 · updated 2026-06-17
• Weakness: CWE-863

Description

Pomerium is an open source identity-aware access proxy. Envoy, which Pomerium is based on, contains two authorization related vulnerabilities CVE-2021-32777 and CVE-2021-32779. This may lead to incorrect routing or authorization policy decisions. With specially crafted requests, incorrect authorization or routing decisions may be made by Pomerium. Pomerium v0.14.8 and v0.15.1 contain an upgraded envoy binary with these vulnerabilities patched. This issue can only be triggered when using path prefix based policy. Removing any such policies should provide mitigation.

Affected products

• envoyproxy envoy: before 1.16.5; from 1.17.0 before 1.17.4; from 1.18.0 before 1.18.4; 1.19.0 — fixed in 1.16.5, 1.17.4, 1.18.4
• pomerium: from 0.11.0 before 0.14.8; 0.15.0 — fixed in 0.14.8

How to fix

Upgrade to a fixed version: envoyproxy envoy 1.16.5, 1.17.4, 1.18.4; pomerium 0.14.8. Check the vendor advisory for mitigations.

References

• https://github.com/envoyproxy/envoy/security/advisories/GHSA-6g4j-5vrw-2m8h
• https://github.com/envoyproxy/envoy/security/advisories/GHSA-r222-74fw-jqr9
• https://github.com/pomerium/pomerium/security/advisories/GHSA-cfc2-wjcm-c8fm
• https://groups.google.com/g/envoy-announce/c/5xBpsEZZDfE/m/wD05NZBbAgAJ
• https://github.com/envoyproxy/envoy/security/advisories/GHSA-6g4j-5vrw-2m8h
• https://github.com/envoyproxy/envoy/security/advisories/GHSA-r222-74fw-jqr9
• https://github.com/pomerium/pomerium/security/advisories/GHSA-cfc2-wjcm-c8fm
• https://groups.google.com/g/envoy-announce/c/5xBpsEZZDfE/m/wD05NZBbAgAJ

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