Auth bypass in Matrix JavaScript Sdk

CVE-2023-29529

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.

Vulnerability class: Broken Access Control

Published · last modified .

CVSS v3 metric

CVSS v3 base score 5.0 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.005 (43.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 43.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2023-29529: held from 0.005 to 0.005.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2023-29529?
CVE-2023-29529 is a medium-severity vulnerability in Matrix JavaScript Sdk, classified under Missing Authorization. CVSS score: 5.0/10. Published 2023-04-14.
How severe is CVE-2023-29529?
Medium severity. CVSS v3 base score is 5.0 out of 10.