# CVE-2022-21657: X.509 Extended Key Usage and Trust Purposes bypass in Envoy

> Envoy fails to validate Extended Key Usage in TLS certificates, allowing attackers to bypass trust restrictions using non-TLS certificates.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Feb 2022
- **Updated:** 23 Apr 2025
- **Also known as:** BIT-envoy-2022-21657, GHSA-837m-wjrv-vm5g

## What is CVE-2022-21657?

CVE-2022-21657 is a medium-severity vulnerability in Envoyproxy Envoy, published on 22 Feb 2022. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2022-21657?

1 open source package ship an affected version, including envoy. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `envoy` | Bitnami | All versions | 1.18.6, 1.19.3, 1.20.2 |

Products: Envoyproxy Envoy.

## How do I fix CVE-2022-21657?

Upgrade envoy to a fixed version for your release line: 1.18.6, 1.19.3 or 1.20.2.

## Is CVE-2022-21657 being exploited?

There is no known exploitation of CVE-2022-21657 in the wild and no public exploit code.

## Other vulnerabilities in Envoyproxy Envoy

- [CVE-2022-29226](https://insights.sbomify.com/CVE-2022-29226/): Trivial authentication bypass in Envoy (critical 10.0)
- [CVE-2019-18801](https://insights.sbomify.com/CVE-2019-18801/): Memory corruption in n/a (critical 9.8)
- [CVE-2019-18802](https://insights.sbomify.com/CVE-2019-18802/): Security feature bypass in n/a (critical 9.8)
- [CVE-2020-35470](https://insights.sbomify.com/CVE-2020-35470/): Information disclosure in n/a (high 8.8)
- [CVE-2024-23324](https://insights.sbomify.com/CVE-2024-23324/): Envoy ext auth can be bypassed when Proxy protocol filter sets invalid UTF-8 metadata (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-21657 and fix it if it is affected.

What it is: CVE-2022-21657 is a medium-severity vulnerability in Envoyproxy Envoy, published on 22 Feb 2022. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2022-21657 in the wild and no public exploit code.

Affected packages and fixed versions:
- envoy (Bitnami): affected all versions; fixed in 1.18.6, 1.19.3, 1.20.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2022-21657/ (Markdown: https://insights.sbomify.com/CVE-2022-21657/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-21657
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-21657
- OSV: https://osv.dev/vulnerability/CVE-2022-21657

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-21657/
Summaries are generated and may contain mistakes; the official description above is the record.