CVE-2021-40824

    Dashboard / Vulnerabilities / CVE-2021-40824

    CVE-2021-40824

    Published: 13 Sept 2021Last Modified: 21 Sept 2026

    Summary:

    Details: 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.

    References: https://matrix.org/blog/2021/09/13/vulnerability-disclosure-key-sharing, https://github.com/matrix-org/matrix-android-sdk2/releases/tag/v1.2.2

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 0
    Fixed -672cf1a46ed84766a5d772169d50afacba23286d

    Affected versions

    v1.2.2-rc.2
    v1.2.2-rc.1

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    CVE-2021-40824 | CVE-DB