PYSEC-2026-844

    Dashboard / Vulnerabilities / PYSEC-2026-844

    PYSEC-2026-844

    Published: 6 Jul 2026Last Modified: 7 Jul 2026

    Summary: Matrix Synapse Authorization Error

    Details: In Synapse before 0.31.2, unauthorised users can hijack rooms when there is no `m.room.power_levels` event in force.

    References: https://nvd.nist.gov/vuln/detail/CVE-2018-12423, https://github.com/matrix-org/matrix-doc/issues/1304, https://bugs.debian.org/901549, https://github.com/matrix-org/synapse, https://matrix.org/blog/2018/06/14/security-update-synapse-0-31-2, https://pypi.org/project/matrix-synapse, https://github.com/advisories/GHSA-ch5v-fhg8-7gv9

    Affected packages

    Package

    Name: matrix-synapse

    Purl: pkg:pypi/matrix-synapse

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -0.31.2

    Affected versions

    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