# CVE-2024-23326: Envoy incorrectly accepts HTTP 200 response for entering upgrade mode

> Attackers can potentially smuggle requests through Envoy if a backend server incorrectly sends a 200 status with an upgrade header, bypassing protocol expectations.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Jun 2024
- **Updated:** 1 Aug 2024
- **Also known as:** BIT-envoy-2024-23326, GHSA-vcf8-7238-v74c

## What is CVE-2024-23326?

CVE-2024-23326 is a medium-severity vulnerability in Envoyproxy Envoy, published on 4 Jun 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Envoy is a cloud-native, open source edge and service proxy. A theoretical request smuggling vulnerability exists through Envoy if a server can be tricked into adding an upgrade header into a response. Per RFC https://www.rfc-editor.org/rfc/rfc7230#section-6.7 a server sends 101 when switching protocols. Envoy incorrectly accepts a 200 response from a server when requesting a protocol upgrade, but 200 does not indicate protocol switch. This opens up the possibility of request smuggling through Envoy if the server can be tricked into adding the upgrade header to the response.

Weakness: CWE-444 (Inconsistent Interpretation of HTTP Requests), CWE-391 (DEPRECATED: Unchecked Error Condition)

## Which versions are affected by CVE-2024-23326?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `envoy` | Bitnami | All versions | 1.27.6, 1.28.4, 1.29.5, 1.30.2 |

Products: Envoyproxy Envoy.

## How do I fix CVE-2024-23326?

Upgrade envoy to a fixed version for your release line: 1.27.6, 1.28.4, 1.29.5 or 1.30.2.

## Is CVE-2024-23326 being exploited?

There is no known exploitation of CVE-2024-23326 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-2024-23326 and fix it if it is affected.

What it is: CVE-2024-23326 is a medium-severity vulnerability in Envoyproxy Envoy, published on 4 Jun 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-23326 in the wild and no public exploit code.

Affected packages and fixed versions:
- envoy (Bitnami): affected all versions; fixed in 1.27.6, 1.28.4, 1.29.5, 1.30.2

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-2024-23326/ (Markdown: https://insights.sbomify.com/CVE-2024-23326/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-23326
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-23326
- OSV: https://osv.dev/vulnerability/CVE-2024-23326

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-23326/
Summaries are generated and may contain mistakes; the official description above is the record.