# CVE-2024-39305: Envoy Proxy use after free when route hash policy is configured with cookie attributes

> Attackers can trigger memory disclosure or crashes in Envoy Proxy when route hash policies use cookie attributes, requiring an upgrade to patched versions.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Jul 2024
- **Updated:** 2 Aug 2024
- **Also known as:** BIT-envoy-2024-39305, GHSA-fp35-g349-h66f

## What is CVE-2024-39305?

CVE-2024-39305 is a medium-severity use after free vulnerability in Envoyproxy Envoy, published on 1 Jul 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. Prior to versions 1.30.4, 1.29.7, 1.28.5, and 1.27.7. Envoy references already freed memory when route hash policy is configured with cookie attributes. Note that this vulnerability has been fixed in the open as the effect would be immediately apparent if it was configured. Memory allocated for holding attribute values is freed after configuration was parsed. During request processing Envoy will attempt to copy content of de-allocated memory into request cookie header. This can lead to arbitrary content of Envoy's memory to be sent to the upstream service or abnormal process termination. This vulnerability is fixed in Envoy versions v1.30.4, v1.29.7, v1.28.5, and v1.27.7. As a workaround, do not use cookie attributes in route action hash policy.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2024-39305?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `envoy` | Bitnami | All versions | 1.27.7, 1.28.5, 1.29.7, 1.30.4 |

Products: Envoyproxy Envoy.

## How do I fix CVE-2024-39305?

Upgrade envoy to a fixed version for your release line: 1.27.7, 1.28.5, 1.29.7 or 1.30.4.

## Is CVE-2024-39305 being exploited?

There is no known exploitation of CVE-2024-39305 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-2024-39305 and fix it if it is affected.

What it is: CVE-2024-39305 is a medium-severity use after free vulnerability in Envoyproxy Envoy, published on 1 Jul 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-2024-39305 in the wild and no public exploit code.

Affected packages and fixed versions:
- envoy (Bitnami): affected all versions; fixed in 1.27.7, 1.28.5, 1.29.7, 1.30.4

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-2024-39305/ (Markdown: https://insights.sbomify.com/CVE-2024-39305/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-39305
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-39305
- OSV: https://osv.dev/vulnerability/CVE-2024-39305

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-39305/
Summaries are generated and may contain mistakes; the official description above is the record.