CVE-2022-39374

Name: CVE-2022-39374
Creator: NVD / NIST
Published: 2023-05-26T14:15:10.257+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.94%

Last modified Jun 17, 2026

CVE-2022-39374 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 0.94% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.94%

56.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Matrix	Synapse	>= 1.62.0, < 1.68.0

References

https://github.com/matrix-org/synapse/pull/13723Issue Tracking, Patch
https://github.com/matrix-org/synapse/security/advisories/GHSA-p9qp-c452-f9r7Mitigation, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD/
https://github.com/matrix-org/synapse/pull/13723Issue Tracking, Patch
https://github.com/matrix-org/synapse/security/advisories/GHSA-p9qp-c452-f9r7Mitigation, Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD/

Timeline

Published: May 26, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-39374?

How severe is CVE-2022-39374?

CVE-2022-39374 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.94% probability of exploitation in the next 30 days.

How do I fix CVE-2022-39374?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2022-39374?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST