CVE-2023-43796

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    CVE-2023-43796

    Published: 31 Oct 2023Last Modified: 28 Oct 2026

    Summary: Synapse vulnerable to leak of remote user device information

    Details: Synapse is an open-source Matrix homeserver Prior to versions 1.95.1 and 1.96.0rc1, cached device information of remote users can be queried from Synapse. This can be used to enumerate the remote users known to a homeserver. System administrators are encouraged to upgrade to Synapse 1.95.1 or 1.96.0rc1 to receive a patch. As a workaround, the `federation_domain_whitelist` can be used to limit federation traffic with a homeserver.

    References: https://lists.fedoraproject.org/archives/list/[email protected]/message/2IDEEZMFJBDLTFHQUTZRJJNCOZGQ2ZVS/, https://lists.fedoraproject.org/archives/list/[email protected]/message/VH3RNC5ZPQZ4OKPSL4E6BBJSZOQLGDEY/, https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/43xxx/CVE-2023-43796.json, https://github.com/matrix-org/synapse/security/advisories/GHSA-mp92-3jfm-3575, https://nvd.nist.gov/vuln/detail/CVE-2023-43796, https://security.gentoo.org/glsa/202401-12, https://github.com/matrix-org/synapse/commit/daec55e1fe120c564240c5386e77941372bf458f

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 0
    Fixed -a11511954a58975d2e5400257a0cecfd27413447

    Affected versions

    v1.95.0
    v1.95.0rc1

    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-2023-43796 | CVE-DB