# CVE-2024-32976: Envoy can enter an endless loop while decompressing Brotli data with extra input

> Attackers can cause an endless loop in Envoy proxy by sending crafted Brotli data, leading to 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:** 4 Jun 2024
- **Updated:** 3 Sep 2024
- **Also known as:** BIT-envoy-2024-32976, GHSA-7wp5-c2vq-4f8m

## What is CVE-2024-32976?

CVE-2024-32976 is a high-severity denial of service 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. Envoyproxy with a Brotli filter can get into an endless loop during decompression of Brotli data with extra input.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2024-32976?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `envoy` | Bitnami | From 1.18.0 | 1.27.6, 1.28.4, 1.29.5, 1.30.2 |

Products: Envoyproxy Envoy.

## How do I fix CVE-2024-32976?

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-2024-32976 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-32976 exists.

## 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-2024-32976 and fix it if it is affected.

What it is: CVE-2024-32976 is a high-severity denial of service 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-32976 exists.

Affected packages and fixed versions:
- envoy (Bitnami): affected from 1.18.0; 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-2024-32976/ (Markdown: https://insights.sbomify.com/CVE-2024-32976/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-32976
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-32976
- OSV: https://osv.dev/vulnerability/CVE-2024-32976

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-32976/
Summaries are generated and may contain mistakes; the official description above is the record.