VULNERABILITY INTELLIGENCE

CVE-2021-40823

CVSS score5.9 MEDIUM
EPSS probability0.66%
CISA KEVNot currently listed
Published2021-09-13
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Description

A logic error in the room key sharing functionality of matrix-js-sdk (aka Matrix Javascript SDK) before 12.4.1 allows a malicious Matrix homeserver present in an encrypted room to steal room encryption keys (via crafted Matrix protocol messages) that were originally sent by affected Matrix clients participating in that room. This allows the homeserver to decrypt end-to-end encrypted messages sent by affected clients.

Weakness classification

  • nvd@nist.gov: CWE-290

Primary references