# CVE-2026-24471: Improper Validation in Conduit-derived homeservers resulting in Unintended Proxy or Intermediary ('Confused Deputy')

> A malicious remote server can trick a Matrix homeserver into signing arbitrary events, enabling event forgery and potential compromise.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:L/SI:L/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 2 Feb 2026
- **Updated:** 3 Feb 2026
- **Also known as:** GHSA-m5p2-vccg-8c9v

## What is CVE-2026-24471?

CVE-2026-24471 is a critical vulnerability in continuwuity, published on 2 Feb 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

continuwuity is a Matrix homeserver written in Rust. This vulnerability allows an attacker with a malicious remote server to cause the local server to sign an arbitrary event upon user interaction. Upon a user account leaving a room (rejecting an invite), joining a room or knocking on a room, the victim server may ask a remote server for assistance. If the victim asks the attacker server for assistance the attacker is able to provide an arbitrary event, which the victim will sign and return to the attacker. For the /leave endpoint, this works for any event with a supported room version, where the origin and origin_server_ts is set by the victim. For the /join endpoint, an additionally victim-set content field in the format of a join membership is needed. For the /knock endpoint, an additional victim-set content field in the format of a knock membership and a room version not between 1 and 6 is needed. This was exploited as a part of a larger chain against the continuwuity.org homeserver. This vulnerability affects all Conduit-derived servers. This vulnerability is fixed in Continuwuity 0.5.1, Conduit 0.10.11, Grapevine 0aae932b, and Tuwunel 1.4.9.

Weakness: CWE-441 (Unintended Proxy or Intermediary)

## Which versions are affected by CVE-2026-24471?


## How do I fix CVE-2026-24471?

No fix has been published for CVE-2026-24471 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-24471 being exploited?

There is no known exploitation of CVE-2026-24471 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-24471 and fix it if it is affected.

What it is: CVE-2026-24471 is a critical vulnerability in continuwuity, published on 2 Feb 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-24471 in the wild and no public exploit code.

Affected product: continuwuity. 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-2026-24471/ (Markdown: https://insights.sbomify.com/CVE-2026-24471/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-24471
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-24471
- OSV: https://osv.dev/vulnerability/CVE-2026-24471

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-24471/
Summaries are generated and may contain mistakes; the official description above is the record.