# CVE-2026-6994: Envoy Query Parameter header_mutation.cc params.add injection

> Remote attackers can inject code via query parameters in Envoy's header mutation filter, potentially leading to code execution.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 Apr 2026
- **Updated:** 27 Apr 2026
- **Also known as:** GHSA-42r9-gr9r-q5q5

## What is CVE-2026-6994?

CVE-2026-6994 is a medium-severity code injection vulnerability in Envoy, published on 25 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A weakness has been identified in Envoy up to 1.33.0. Affected is the function params.add of the file source/extensions/filters/http/header_mutation/header_mutation.cc of the component Query Parameter Handler. This manipulation causes injection. Remote exploitation of the attack is possible. Patch name: f8f4f1e02fdc64ecd4acf2d903208dd7285ad3a4. It is suggested to install a patch to address this issue.

Weakness: CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component), CWE-707 (Improper Neutralization)

## Which versions are affected by CVE-2026-6994?


## How do I fix CVE-2026-6994?

No fix has been published for CVE-2026-6994 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-6994 being exploited?

There is no known exploitation of CVE-2026-6994 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6994 and fix it if it is affected.

What it is: CVE-2026-6994 is a medium-severity code injection vulnerability in Envoy, published on 25 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-6994 in the wild and no public exploit code.

Affected product: Envoy. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-6994/ (Markdown: https://insights.sbomify.com/CVE-2026-6994/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6994
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6994
- OSV: https://osv.dev/vulnerability/CVE-2026-6994

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-6994/
Summaries are generated and may contain mistakes; the official description above is the record.