CVE-2022-39335

Synapse does not apply enough checks to servers requesting auth events of events in a room

MEDIUM
5
CVSS Score
Published: May 26, 2023 at 01:36 PM UTC
Updated: June 17, 2026 at 04:58 AM UTC
2 products affected across 2 vendorsSynapseSynapse

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Severity
MEDIUM5
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.69.0
Affected range stops below 1.69.0, so it looks safe — our inference, not a vendor statement
v < 1.69.0
Affected range stops below 1.69.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
LOW
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-200CWE-862

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