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

Medium 5.0 Published Updated

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

Exploited in the wild
Not known
Login needed
Any signed-in user
Attackable
Over the internet
Victim action needed
Not needed
Fix
Available

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

Which versions are affected by CVE-2023-29529?

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

PackageAffectedFixed in
matrix-js-sdk npmAll versions24.1.0
matrix-js-sdk npmAll versions24.1.0

Products include Matrix Javascript Sdk.

How do I fix CVE-2023-29529?

Upgrade matrix-js-sdk to 24.1.0 or later.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2023-29529 being exploited?

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

Sources

Also known as DEBIAN-CVE-2023-29529, GHSA-6g67-q39g-r79q, UBUNTU-CVE-2023-29529.

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