# CVE-2023-29529: matrix-js-sdk vulnerable to invisible eavesdropping in group calls

> An attacker in a Matrix group call can secretly eavesdrop on audio and video without appearing as a participant due to missing authorization checks.

- **Severity:** Medium 5.0 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Apr 2023
- **Updated:** 6 Feb 2025
- **Also known as:** DEBIAN-CVE-2023-29529, GHSA-6g67-q39g-r79q, UBUNTU-CVE-2023-29529

## What is CVE-2023-29529?

CVE-2023-29529 is a medium-severity missing authorization vulnerability in matrix-org matrix-js-sdk, published on 14 Apr 2023. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

matrix-js-sdk is the Matrix Client-Server SDK for JavaScript and TypeScript. An attacker present in a room where an MSC3401 group call is taking place can eavesdrop on the video and audio of participants using matrix-js-sdk, without their knowledge. To affected matrix-js-sdk users, the attacker will not appear to be participating in the call. This attack is possible because matrix-js-sdk's group call implementation accepts incoming direct calls from other users, even if they have not yet declared intent to participate in the group call, as a means of resolving a race condition in call setup. Affected versions do not restrict access to the user's outbound media in this case. Legacy 1:1 calls are unaffected. This is fixed in matrix-js-sdk 24.1.0. As a workaround, users may hold group calls in private rooms where only the exact users who are expected to participate in the call are present.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2023-29529?

2 open source packages ship an affected version, including matrix-js-sdk. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `matrix-js-sdk` | npm | All versions | 24.1.0 |
| `matrix-js-sdk` | npm | All versions | 24.1.0 |

Products: Matrix Javascript Sdk.

## How do I fix CVE-2023-29529?

Upgrade matrix-js-sdk to 24.1.0 or later.

## Is CVE-2023-29529 being exploited?

There is no known exploitation of CVE-2023-29529 in the wild and no public exploit code.

## Other vulnerabilities in matrix-org matrix-js-sdk

- [CVE-2022-39250](https://insights.sbomify.com/CVE-2022-39250/): Matrix JavaScript SDK vulnerable to key/device identifier confusion in SAS verification (high 8.6)
- [CVE-2022-39251](https://insights.sbomify.com/CVE-2022-39251/): Matrix Javascript SDK vulnerable to Olm/Megolm protocol confusion (high 8.6)
- [CVE-2022-36059](https://insights.sbomify.com/CVE-2022-36059/): Prototype pollution in matrix-js-sdk (high 8.2)
- [CVE-2023-28427](https://insights.sbomify.com/CVE-2023-28427/): Prototype pollution in matrix-js-sdk (high 8.2)
- [CVE-2022-39249](https://insights.sbomify.com/CVE-2022-39249/): Matrix Javascript SDK vulnerable to impersonation via forwarded Megolm sessions (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-29529 and fix it if it is affected.

What it is: CVE-2023-29529 is a medium-severity missing authorization vulnerability in matrix-org matrix-js-sdk, published on 14 Apr 2023. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-29529 in the wild and no public exploit code.

Affected packages and fixed versions:
- matrix-js-sdk (npm): affected all versions; fixed in 24.1.0
- matrix-js-sdk (npm): affected all versions; fixed in 24.1.0

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-2023-29529/ (Markdown: https://insights.sbomify.com/CVE-2023-29529/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-29529
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-29529
- OSV: https://osv.dev/vulnerability/CVE-2023-29529

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-29529/
Summaries are generated and may contain mistakes; the official description above is the record.