Summary
matrix-js-sdk vulnerable to invisible eavesdropping in group calls
Workarounds
Users may hold group calls in private rooms where only the exact users who are expected to participate in the call are present.
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.
The application does not perform an authorization check before performing a sensitive operation. Typical impact: unauthorized access to restricted functionality or data.
CVE-2023-29529 has a CVSS score of 5.0 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (24.1.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2023-29529? CVE-2023-29529 is a medium-severity missing authorization vulnerability in matrix-js-sdk (npm), affecting versions < 24.1.0. It is fixed in 24.1.0. The application does not perform an authorization check before performing a sensitive operation.
- How severe is CVE-2023-29529? CVE-2023-29529 has a CVSS score of 5.0 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of matrix-js-sdk are affected by CVE-2023-29529? matrix-js-sdk (npm) versions < 24.1.0 is affected.
- Is there a fix for CVE-2023-29529? Yes. CVE-2023-29529 is fixed in 24.1.0. Upgrade to this version or later.
- Is CVE-2023-29529 exploitable, and should I be worried? Whether CVE-2023-29529 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2023-29529 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2023-29529? Upgrade
matrix-js-sdkto 24.1.0 or later.