UBUNTU-CVE-2021-40823

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    UBUNTU-CVE-2021-40823

    Published: 13 Sept 2021Last Modified: 24 Oct 2025
    Upstream:
    CVE-2021-40823

    Summary:

    Details: 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.

    References: https://ubuntu.com/security/CVE-2021-40823, https://matrix.org/blog/2021/09/13/vulnerability-disclosure-key-sharing/, https://github.com/matrix-org/matrix-js-sdk/commit/894c24880da0e1cc81818f51c0db80e3c9fb2be9, https://github.com/matrix-org/matrix-js-sdk/releases/tag/v12.4.1, https://matrix.org/blog/2021/09/13/vulnerability-disclosure-key-sharing, https://www.cve.org/CVERecord?id=CVE-2021-40823

    Affected packages

    Package

    Name: node-matrix-js-sdk

    Purl: pkg:deb/ubuntu/[email protected]?arch=source&distro=focal

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    0.9.2-1

    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
    UBUNTU-CVE-2021-40823 | CVE-DB