matrix-js-sdk vulnerable to invisible eavesdropping in group calls

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.0 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N

EPSS

• CVE-2023-29529: 0.54% estimated exploitation activity in the next 30 days; percentile 45.66 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact 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. Workarounds Users may hold group calls in private rooms where only the exact users who are expected to participate in the call are present.

Published by the source

14 Apr 2023, 16:14 UTC

Last modified by the source

10 Sep 2026, 03:49 UTC

Source last checked

26 Oct 2026, 12:22 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-6g67-q39g-r79q

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-6g67-q39g-r79q

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# Patch Next advisory brief: CVE-2023-29529

Advisory: matrix-js-sdk vulnerable to invisible eavesdropping in group calls
IDs: CVE-2023-29529, GHSA-6g67-q39g-r79q
Record: https://patchnext.com/advisories/cve-2023-29529 (revision 2, source checked 26 Oct 2026, 12:22 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: matrix-js-sdk 24.1.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm matrix-js-sdk: affected < 24.1.0; fixed in 24.1.0

## Suggested inspection (read-only)
- `npm ls matrix-js-sdk --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on matrix-js-sdk.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-6g67-q39g-r79q (OSV record GHSA-6g67-q39g-r79q lists affected ranges: npm matrix-js-sdk >=0 <24.1.0 (fixed))
- Verified: https://github.com/advisories/GHSA-6g67-q39g-r79q (GitHub-reviewed advisory GHSA-6g67-q39g-r79q lists affected ranges: npm matrix-js-sdk >=0 <24.1.0)

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