# CVE-2022-39374: Synapse Denial of service due to incorrect application of event authorization rules during state resolution

Source: https://junglewise.ai/threats/cve-2022-39374-synapse-denial-of-service-due-to-incorrect-application-of-event  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2023-05-26  
License: CC BY 4.0 with a link back

CVE-2022-39374 · Severity: low · CVSS 3.1 · Published 2023-05-26

Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. If Synapse and a malicious homeserver are both joined to the same room, the malicious homeserver can trick Synapse into accepting previously rejected events into its view of the current state of that room. This can be exploited in a way that causes all further messages and state changes sent in that room from the vulnerable homeserver to be rejected. This issue has been patched in version 1.68.0

Technologies: [matrix-synapse (PyPI)](https://junglewise.ai/threats/technologies/matrix-synapse). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2022-39374 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2022-39374 being exploited in the wild.

**How severe is CVE-2022-39374?** Low severity, with a CVSS score of 3.1, published 26 May 2023.

**Which products and versions are affected?** matrix-synapse (PyPI) ECOSYSTEM:introduced=1.62.0,fixed=1.68.0, ECOSYSTEM:introduced=1.62.0,fixed=1.68.0rc1.

**Is there a fix for CVE-2022-39374?** Yes. matrix-synapse (PyPI): upgrade to 1.68.0, 1.68.0rc1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2022-39374?** 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 1.68.0, 1.68.0rc1 or later

  ```sh
  pip install "matrix-synapse>=1.68.0rc1"
  ```


## Affected products

- matrix-synapse (PyPI) ECOSYSTEM:introduced=1.62.0,fixed=1.68.0, ECOSYSTEM:introduced=1.62.0,fixed=1.68.0rc1

## Identifiers

- CVE-2022-39374
- GHSA-p9qp-c452-f9r7
- PYSEC-2023-66

## Related threats

- [PYSEC-2026-2620 - matrix-sydent and matrix-synapse Use Cryptographically Weak PRNG](https://junglewise.ai/threats/cve-2019-11842-matrix-sydent-and-matrix-synapse-use-cryptographically-weak-prng)
- [PYSEC-2026-1614 - Synapse vulnerable to federation denial of service via malformed events](https://junglewise.ai/threats/cve-2025-30355-synapse-vulnerable-to-federation-denial-of-service-via-malformed)
- [PYSEC-2026-1610 - Synapse Matrix has a partial room state leak via Sliding Sync](https://junglewise.ai/threats/cve-2024-53867-synapse-matrix-has-a-partial-room-state-leak-via-sliding-sync)
- [Synapse can be forced to thumbnail unexpected file formats, invoking external, potentially untrustworthy decoders](https://junglewise.ai/threats/cve-2024-53863-synapse-can-be-forced-to-thumbnail-unexpected-file-formats)
- [PYSEC-2026-1611 - Synapse allows a a malformed invite to break the invitee's `/sync`](https://junglewise.ai/threats/cve-2024-52815-synapse-allows-a-a-malformed-invite-to-break-the-invitee-s-sync)