matrix-js-sdk can be tricked into disclosing E2EE room keys to a participating homeserver

Description

A logic error in the room key sharing functionality of matrix-js-sdk before 12.4.1 allows a malicious Matrix homeserver† participating in an encrypted room to steal room encryption keys from affected Matrix clients participating in that room. This allows the homeserver to decrypt end-to-end encrypted messages sent by affected clients.

Recommendation

Update the matrix-js-sdk package to the latest compatible version. Followings are version details:

• Affected version(s): < 12.4.1
• Patched version(s): 12.4.1

References

• GHSA-23cm-x6j7-6hq3
• matrix.org
• CVE-2021-40823
• CWE-200
• CWE-327
• CAPEC-310
• OWASP 2021-A1
• OWASP 2021-A2
• OWASP 2021-A6

Related Issues

• matrix-js-sdk has insufficient MXC URI validation which allows client-side path traversal - CVE-2024-50336
• Vega allows Cross-site Scripting via the vlSelectionTuples function (GHSA-mp7w-mhcv-673j) - CVE-2025-25304
• matrix-js-sdk has insufficient validation when considering a room to be upgraded by another - CVE-2025-59160
• Matrix JavaScript SDK's key history sharing could share keys to malicious devices - CVE-2024-47080

Tags:

npm

matrix-js-sdk