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Fencer Vulns
medium 6.8

CVE-2022-21657 json

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

published 2022-02-22 4 y ago modified 2026-09-08 2 mo ago also BIT-envoy-2022-21657 , EUVD-2022-26875 , GHSA-837m-wjrv-vm5g

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

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.

Patch / fix

  • bitnami envoy 1.18.6, 1.19.3, 1.20.2
  • envoyproxy envoy 1.18.6, 1.19.3, 1.20.2

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2022-21657 updated cvss 6.8

envoy: X.509 Extended Key Usage and Trust Purposes bypass

  • Red Hat OpenShift Service Mesh 2.0 servicemesh-proxy
    affected: no fix available
  • Red Hat OpenShift Service Mesh 2.1 servicemesh-proxy, servicemesh-proxy-wasm
    affected: no fix planned “Will not fix”
  • Red Hat OpenShift Service Mesh 2 openshift-service-mesh/proxyv2-rhel8
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
18 mo ago

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:P/A:N
OSV 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
bitnami envoy
<1.18.6
>=1.19.0, <1.19.3
>=1.20.0, <1.20.2
1.18.6
1.19.3
1.20.2

Affected products

  • envoyproxy envoy

Classification

Weakness
  • CWE-295 Improper Certificate Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.