CVE-2022-39335Network attack vector

Room authorization-event disclosure via missing federation access check

Published May 26, 2023 · Updated Feb 13, 2025

Information disclosure in Matrix.org Synapse before 1.69.0 allows remote attackers to read room authorization events through federation. The federation event-auth endpoint returns an event's authorization chain without confirming that the requesting homeserver may access the room. Exploitation requires the target room and event IDs; message contents are not exposed, and closed federations containing only trusted servers are unaffected.

CVSS severity5.0
Medium
EPSS probability0.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Matrix.org Synapse before 1.69.0 allows remote attackers to read room authorization events through federation. The federation event-auth endpoint returns an event's authorization chain without confirming that the requesting homeserver may access the room. Exploitation requires the target room and event IDs; message contents are not exposed, and closed federations containing only trusted servers are unaffected.

The record

CVE
CVE-2022-39335
Published
May 26, 2023
Updated
Feb 13, 2025
Vendor
Matrix.org
Product
Synapse
Classifications
CWE-200, CWE-862, T1213.005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 26, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.69.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Matrix.org · Synapseversion=< 1.69.0

Published CVSS scores

5.0NIST NVDCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
CWE-862Missing Authorization
T1213.005Data from Information Repositories: Messaging Applications

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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