How severe is CVE-2022-39335?

CVE-2022-39335 has a CVSS 3.x base score of 5.0, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2022-39335 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2022-39335?

CVE-2022-39335 affects Matrix Synapse. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2022-39335?

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

When was CVE-2022-39335 published?

CVE-2022-39335 was published on 2023-05-26 and last updated on 2026-06-17.

CVE-2022-39335

CVE-2022-39335 is a medium-severity vulnerability in Matrix Synapse with a CVSS 3.x base score of 5.0. 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-862.

Key facts

Severity: Medium (CVSS 3.x base score 5.0)
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-862
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. The Matrix Federation API allows remote homeservers to request the authorization events in a room. This is necessary so that a homeserver receiving some events can validate that those events are legitimate and permitted in their room. However, in versions of Synapse up to and including 1.68.0, a Synapse homeserver answering a query for authorization events does not sufficiently check that the requesting server should be able to access them. The issue was patched in Synapse 1.69.0. Homeserver administrators are advised to upgrade.

Frequently asked questions

What is CVE-2022-39335?: Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. The Matrix Federation API allows remote homeservers to request the authorization events in a room. This is necessary so that a homeserver receiving some events can validate that those events are legitimate and permitted in their room. However, in versions of Synapse up to and including 1.68.0, a Synapse homeserver answering a query for authorization events does not sufficiently check that the requesting server should be able to access them. The issue was patched in Synapse 1.69.0. Homeserver administrators are advised to upgrade.
How severe is CVE-2022-39335?: CVE-2022-39335 has a CVSS 3.x base score of 5.0, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2022-39335 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-39335?: CVE-2022-39335 affects Matrix Synapse. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2022-39335?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2022-39335 published?: CVE-2022-39335 was published on 2023-05-26 and last updated on 2026-06-17.

References

Affected products (1)

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

More vulnerabilities in Matrix Synapse

CVE-2019-18835 — Critical (CVSS 9.8): Matrix Synapse before 1.5.0 mishandles signature checking on some federation APIs. Events sent over /send_join,…
CVE-2024-53863 — Critical (CVSS 9.1): Synapse is an open-source Matrix homeserver. In Synapse versions before 1.120.1, enabling the dynamic_thumbnails option…
CVE-2018-16515 — High (CVSS 8.8): Matrix Synapse before 0.33.3.1 allows remote attackers to spoof events and possibly have unspecified other impacts by…
CVE-2024-52805 — High (CVSS 7.5): Synapse is an open-source Matrix homeserver. In Synapse before 1.120.1, multipart/form-data requests can in certain…
CVE-2024-37302 — High (CVSS 7.5): Synapse is an open-source Matrix homeserver. Synapse versions before 1.106 are vulnerable to a disk fill attack, where…
CVE-2021-41281 — High (CVSS 7.5): Synapse is a package for Matrix homeservers written in Python 3/Twisted. Prior to version 1.47.1, Synapse instances…

All CVEs affecting Matrix Synapse →

Other CWE-862 (Missing Authorization) vulnerabilities

CVE-2026-0092 — Critical (CVSS 10.0): In Package Manager, there is a possible device lock controller bypass due to a missing permission check. This could…
CVE-2026-33712 — Critical (CVSS 10.0): Typebot is a chatbot builder tool. In versions 3.15.2 and prior, the preview chat endpoint (POST…
CVE-2026-2031 — Critical (CVSS 10.0): An Improper Access Control vulnerability in several internal API endpoints for Google Cloud Application Integration…
CVE-2026-34976 — Critical (CVSS 10.0): Dgraph is an open source distributed GraphQL database. Prior to 25.3.1, the restoreTenant admin mutation is missing…
CVE-2025-30416 — Critical (CVSS 10.0): Sensitive data disclosure and manipulation due to missing authorization. The following products are affected: Acronis…
CVE-2025-45854 — Critical (CVSS 10.0): /server/executeExec of JEHC-BPM 2.0.1 allows attackers to execute arbitrary code via execParams.

Browse all CWE-862 (Missing Authorization) vulnerabilities →