CVE-2023-45129: matrix-synapse vulnerable to denial of service due to malicious server ACL events

CVE-2023-45129 · Severity: low · CVSS 3.1 · Published 2023-10-10

Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Prior to version 1.94.0, a malicious server ACL event can impact performance temporarily or permanently leading to a persistent denial of service. Homeservers running on a closed federation (which presumably do not need to use server ACLs) are not affected. Server administrators are advised to upgrade to Synapse 1.94.0 or later. As a workaround, rooms with malicious server ACL events can be purged and blocked using the admin API.

Technologies: matrix-synapse (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2023-45129 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2023-45129 being exploited in the wild.
How severe is CVE-2023-45129?
Low severity, with a CVSS score of 3.1, published 10 October 2023.
Which products and versions are affected?
matrix-synapse (PyPI) ECOSYSTEM:introduced=0,fixed=1.94.0.
Is there a fix for CVE-2023-45129?
Yes. matrix-synapse (PyPI): upgrade to 1.94.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2023-45129?
Check whether you run matrix-synapse (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • matrix-synapse (PyPI): upgrade to 1.94.0 or later
    pip install "matrix-synapse>=1.94.0"

Affected products

  • matrix-synapse (PyPI) ECOSYSTEM:introduced=0,fixed=1.94.0

Identifiers

  • CVE-2023-45129
  • GHSA-5chr-wjw5-3gq4
  • PYSEC-2023-199

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