# CVE-2024-23327: Crash in proxy protocol when command type of LOCAL in Envoy

> Attackers can crash Envoy proxy instances by sending specific proxy protocol headers when PPv2 is enabled on both listener and cluster.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Feb 2024
- **Updated:** 9 Jun 2025
- **Also known as:** BIT-envoy-2024-23327, GHSA-4h5x-x9vh-m29j

## What is CVE-2024-23327?

CVE-2024-23327 is a high-severity vulnerability in Envoyproxy Envoy, published on 9 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Envoy is a high-performance edge/middle/service proxy. When PPv2 is enabled both on a listener and subsequent cluster, the Envoy instance will segfault when attempting to craft the upstream PPv2 header. This occurs when the downstream request has a command type of LOCAL and does not have the protocol block. This issue has been addressed in releases 1.29.1, 1.28.1, 1.27.3, and 1.26.7. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2024-23327?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `envoy` | Bitnami | From 1.26.0 | 1.26.7, 1.27.3, 1.28.1, 1.29.1 |

Products: Envoyproxy Envoy.

## How do I fix CVE-2024-23327?

Upgrade envoy to a fixed version for your release line: 1.26.7, 1.27.3, 1.28.1 or 1.29.1.

## Is CVE-2024-23327 being exploited?

There is no known exploitation of CVE-2024-23327 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-2024-23327 and fix it if it is affected.

What it is: CVE-2024-23327 is a high-severity vulnerability in Envoyproxy Envoy, published on 9 Feb 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-2024-23327 in the wild and no public exploit code.

Affected packages and fixed versions:
- envoy (Bitnami): affected from 1.26.0; fixed in 1.26.7, 1.27.3, 1.28.1, 1.29.1

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-2024-23327/ (Markdown: https://insights.sbomify.com/CVE-2024-23327/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-23327
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-23327
- OSV: https://osv.dev/vulnerability/CVE-2024-23327

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-23327/
Summaries are generated and may contain mistakes; the official description above is the record.