# CVE-2026-41873: Pony Mail: Admin account takeover via request smuggling

> HTTP request smuggling in the retired Lua implementation of Apache Pony Mail allows attackers to take over admin accounts.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 Apr 2026
- **Updated:** 29 Apr 2026
- **Also known as:** GHSA-cvw6-x8c3-583g

## What is CVE-2026-41873?

CVE-2026-41873 is a critical vulnerability in Apache Software Foundation Pony Mail, published on 28 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

** UNSUPPORTED WHEN ASSIGNED ** Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in Pony Mail leading to admin account takeover.

This issue affects all versions of the Lua implementation of Pony Mail. There is a Python implementation under development under the name "Pony Mail Foal" that is not affected by this issue, but hasn't been released yet.

As the Lua implementation of this project is retired, we do not plan to release a version that fixes this issue. Users are recommended to find an alternative or restrict access to the instance to trusted users.

NOTE: This vulnerability only affects products that are no longer supported by the maintainer.

Weakness: CWE-444 (Inconsistent Interpretation of HTTP Requests)

## Which versions are affected by CVE-2026-41873?

It affects 1 product.


Products: Apache Pony Mail.

## How do I fix CVE-2026-41873?

No fix has been published for CVE-2026-41873 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-41873 being exploited?

There is no known exploitation of CVE-2026-41873 in the wild and no public exploit code.

## Other vulnerabilities in Apache Software Foundation Pony Mail

- [CVE-2016-4460](https://insights.sbomify.com/CVE-2016-4460/): Auth bypass in n/a (critical 9.8)
- [CVE-2019-0218](https://insights.sbomify.com/CVE-2019-0218/): Cross-site scripting in Apache Pony Mail (incubating) (medium 6.1)
- [CVE-2017-5658](https://insights.sbomify.com/CVE-2017-5658/): Information disclosure in Apache Pony Mail (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-41873 and fix it if it is affected.

What it is: CVE-2026-41873 is a critical vulnerability in Apache Software Foundation Pony Mail, published on 28 Apr 2026. 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-2026-41873 in the wild and no public exploit code.

Affected product: Apache Software Foundation Pony Mail. 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-2026-41873/ (Markdown: https://insights.sbomify.com/CVE-2026-41873/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-41873
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-41873
- OSV: https://osv.dev/vulnerability/CVE-2026-41873

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-41873/
Summaries are generated and may contain mistakes; the official description above is the record.