VULNERABILITY INTELLIGENCE

CVE-2021-40824

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 Element Android before 1.2.2 and matrix-android-sdk2 (aka Matrix SDK for Android) before 1.2.2 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 attacker to decrypt end-to-end encrypted messages sent by affected clients.

Weakness classification

nvd@nist.gov: CWE-290

Primary references

cve@mitre.org — Patch, Third Party Advisory
cve@mitre.org — Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108 — Patch, Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108 — Vendor Advisory