How severe is CVE-2022-39374?

CVE-2022-39374 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2022-39374 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (57th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2022-39374?

CVE-2022-39374 affects Matrix Synapse. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2022-39374?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2022-39374 published?

CVE-2022-39374 was published on 2023-05-26 and last updated on 2026-06-17.

CVE-2022-39374

CVE-2022-39374 is a medium-severity vulnerability in Matrix Synapse with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-400.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 1% (57th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-400
Affected product: Matrix Synapse
Published: 2023-05-26
Last modified: 2026-06-17

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

Frequently asked questions

What is CVE-2022-39374?: 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
How severe is CVE-2022-39374?: CVE-2022-39374 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2022-39374 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (57th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-39374?: CVE-2022-39374 affects Matrix Synapse. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2022-39374?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2022-39374 published?: CVE-2022-39374 was published on 2023-05-26 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*

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