TI-2022-06035 Aliases CVE-2022-21657

X.509 Extended Key Usage and Trust Purposes bypass in Envoy

LOW 33CWE-295Published 2022-02-22 · Updated 2025-04-23

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: High
Impact type: Spoofing
Confidentiality · integrity · availability: High · High · None
Fix status: Partial Red Hat: 2 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-295.

Summary

Envoy is an open source edge and service proxy, designed for cloud-native applications. In affected versions Envoy does not restrict the set of certificates it accepts from the peer, either as a TLS client or a TLS server, to only those certificates that contain the necessary extendedKeyUsage (id-kp-serverAuth and id-kp-clientAuth, respectively). This means that a peer may present an e-mail certificate (e.g. id-kp-emailProtection), either as a leaf certificate or as a CA in the chain, and it will be accepted for TLS. This is particularly bad when combined with the issue described in pull request #630, in that it allows a Web PKI CA that is intended only for use with S/MIME, and thus exempted from audit or supervision, to issue TLS certificates that will be accepted by Envoy. As a result Envoy will trust upstream certificates that should not be trusted. There are no known workarounds to this issue. Users are advised to upgrade.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00522 44th percentileScored 2026-11-07

Fix Partial envoy (envoyproxy): 1.20.2, 1.19.3, 1.18.6Red Hat: 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
envoyproxy	envoy	1.20.0 to before 1.20.2; 1.19.0 to before 1.19.3; before 1.18.6	1.20.2, 1.19.3, 1.18.6	Patch available	CNA

envoy Vendorenvoyproxy Affected 1.20.0 to before 1.20.2; 1.19.0 to before 1.19.3; before 1.18.6 Fixed in 1.20.2, 1.19.3, 1.18.6 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:envoyproxy:envoy::::::::	before 1.18.6; 1.19.0 to before 1.19.3; 1.20.0 to before 1.20.2	Vulnerable	envoyproxy

cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* Versions before 1.18.6; 1.19.0 to before 1.19.3; 1.20.0 to before 1.20.2 Vulnerable ·envoyproxy

Remediation

Fix · CNA envoy (envoyproxy) Fixed in 1.20.2, 1.19.3, 1.18.6

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
OpenShift Service Mesh 2.0	Affected	No fix yet
OpenShift Service Mesh 2.1	Affected	No fix planned: Will not fix

Not affected: 1 product

OpenShift Service Mesh 2

Timeline

2026-10-02 Threatist record created from CVE-2022-21657

References

Patch 1

https://github.com/envoyproxy/envoy/pull/630

Advisory 1

https://github.com/envoyproxy/envoy/security/advisories/GHSA-837m-wjrv-vm5g

TI-2026-79288 Out-of-bounds write in Google Brotli decoder KEVCVSS 4.0CRITICAL 9.2
TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
TI-2024-20001 HTTP/2: CPU exhaustion due to CONTINUATION frame flood CVSS 3.1HIGH 7.5
TI-2024-18524 HTTP/2: memory exhaustion due to CONTINUATION frame flood CVSS 3.1HIGH 7.5
TI-2023-12215 Envoy client may fake the header `x-envoy-original-path` CVSS 3.1CRITICAL 9.1
TI-2023-18002 Envoy vulnerable to OAuth2 credentials exploit with permanent validity CVSS 3.1CRITICAL 9.8

See all 126 →

Sources

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