QID 980024

QID 980024: Python (pip) Security Update for matrix-synapse (GHSA-3hfw-x7gx-437c)

Security update has been released for matrix-synapse to fix the vulnerability.

Note: The preceding description block is extracted directly from the security advisory. Using automation, we have attempted to clean and format it as much as possible without introducing additional issues.

Synapse instances with the media repository enabled can be tricked into downloading a file from a remote server into an arbitrary directory, potentially outside the media store directory.

The last two directories and file name of the path are chosen randomly by Synapse and cannot be controlled by an attacker, which limits the impact.

Homeservers with the media repository disabled are unaffected. Homeservers configured with a federation whitelist are also unaffected.

  • CVSS V3 rated as High - 7.5 severity.
  • CVSS V2 rated as Medium - 4.3 severity.
    • Solution
    Server administrators should upgrade to 1.47.1 or later.Workaround:
    Server administrators using a reverse proxy could, at the expense of losing media functionality, block the following endpoints:

    * `/_matrix/media/r0/download/{serverName}/{mediaId}`
    * `/_matrix/media/r0/download/{serverName}/{mediaId}/{fileName}`
    * `/_matrix/media/r0/thumbnail/{serverName}/{mediaId}`

    Alternatively, non-containerized deployments can be adapted to use the hardened systemd config, located at `contrib/systemd/override-hardened.conf`.
    Vendor References

    CVEs related to QID 980024

    CVE-2021-41281 |
    Software Advisories
    Advisory ID Software Component Link
    GHSA-3hfw-x7gx-437c matrix-synapse URL Logo github.com/advisories/GHSA-3hfw-x7gx-437c
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