# CVE-2024-32475: Envoy RELEASE_ASSERT using auto_sni with :authority header > 255 bytes

> Attackers can crash Envoy proxy by sending long authority headers when auto_sni is enabled, causing service disruption.

- **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:** 18 Apr 2024
- **Updated:** 2 Aug 2024
- **Also known as:** BIT-envoy-2024-32475, GHSA-3mh5-6q8v-25wj

## What is CVE-2024-32475?

CVE-2024-32475 is a high-severity denial of service vulnerability in Envoyproxy Envoy, published on 18 Apr 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. When an upstream TLS cluster is used with `auto_sni` enabled, a request containing a `host`/`:authority` header longer than 255 characters triggers an abnormal termination of Envoy process. Envoy does not gracefully handle an error when setting SNI for outbound TLS connection. The error can occur when Envoy attempts to use the `host`/`:authority` header value longer than 255 characters as SNI for outbound TLS connection. SNI length is limited to 255 characters per the standard. Envoy always expects this operation to succeed and abnormally aborts the process when it fails. This vulnerability is fixed in 1.30.1, 1.29.4, 1.28.3, and 1.27.5.

Weakness: CWE-617 (Reachable Assertion), CWE-253 (Incorrect Check of Function Return Value)

## Which versions are affected by CVE-2024-32475?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `envoy` | Bitnami | From 1.13.0 | 1.27.5, 1.28.3, 1.29.4, 1.30.1 |

Products: Envoyproxy Envoy.

## How do I fix CVE-2024-32475?

Upgrade envoy to a fixed version for your release line: 1.27.5, 1.28.3, 1.29.4 or 1.30.1.

## Is CVE-2024-32475 being exploited?

There is no known exploitation of CVE-2024-32475 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-2024-32475 and fix it if it is affected.

What it is: CVE-2024-32475 is a high-severity denial of service vulnerability in Envoyproxy Envoy, published on 18 Apr 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-2024-32475 in the wild and no public exploit code.

Affected packages and fixed versions:
- envoy (Bitnami): affected from 1.13.0; fixed in 1.27.5, 1.28.3, 1.29.4, 1.30.1

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-2024-32475/ (Markdown: https://insights.sbomify.com/CVE-2024-32475/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-32475
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-32475
- OSV: https://osv.dev/vulnerability/CVE-2024-32475

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-32475/
Summaries are generated and may contain mistakes; the official description above is the record.