# CVE-2026-43506: Denial of service in Prosody

> Unauthenticated attackers can cause a Denial of Service in Prosody XMPP server by exhausting memory through connection leaks.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 May 2026
- **Updated:** 1 May 2026
- **Also known as:** DEBIAN-CVE-2026-43506, GHSA-q553-9xvw-ww8h, UBUNTU-CVE-2026-43506

## What is CVE-2026-43506?

CVE-2026-43506 is a medium-severity denial of service vulnerability in Prosody, published on 1 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in Prosody before 0.12.6 and 1.0.0 through 13.0.0 before 13.0.5. A Denial of Service can occur via memory exhaustion caused by memory leaks from unauthenticated connections.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2026-43506?

It affects 1 product.


Products: Prosody Prosody.

## How do I fix CVE-2026-43506?

Upgrade to a fixed version.

## Is CVE-2026-43506 being exploited?

There is no known exploitation of CVE-2026-43506 in the wild and no public exploit code.

## Other vulnerabilities in Prosody

- [CVE-2014-2745](https://insights.sbomify.com/CVE-2014-2745/): Denial of service in n/a (high 7.8)
- [CVE-2022-0217](https://insights.sbomify.com/CVE-2022-0217/): XML external entity in prosody (high 7.5)
- [CVE-2021-37601](https://insights.sbomify.com/CVE-2021-37601/): Information disclosure in n/a (high 7.5)
- [CVE-2026-43504](https://insights.sbomify.com/CVE-2026-43504/): Missing authorization in Prosody (medium 6.5)
- [CVE-2026-43505](https://insights.sbomify.com/CVE-2026-43505/): Missing authorization in Prosody (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43506 and fix it if it is affected.

What it is: CVE-2026-43506 is a medium-severity denial of service vulnerability in Prosody, published on 1 May 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-2026-43506 in the wild and no public exploit code.

Affected product: Prosody. 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-2026-43506/ (Markdown: https://insights.sbomify.com/CVE-2026-43506/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43506
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43506
- OSV: https://osv.dev/vulnerability/CVE-2026-43506

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43506/
Summaries are generated and may contain mistakes; the official description above is the record.