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Synapse vulnerable to leak of remote user device information

Moderate severity GitHub Reviewed Published Oct 31, 2023 in matrix-org/synapse • Updated Jan 8, 2024

Package

pip matrix-synapse (pip)

Affected versions

< 1.95.1

Patched versions

1.95.1

Description

Impact

Cached device information of remote users can be queried from Synapse. This can be used to enumerate the remote users known to a homeserver.

Patches

System administrators are encouraged to upgrade to Synapse 1.95.1 as soon as possible.

Workarounds

The federation_domain_whitelist can be used to limit federation traffic with a homeserver.

References

@erikjohnston erikjohnston published to matrix-org/synapse Oct 31, 2023
Published by the National Vulnerability Database Oct 31, 2023
Published to the GitHub Advisory Database Oct 31, 2023
Reviewed Oct 31, 2023
Last updated Jan 8, 2024

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS score

0.188%
(57th percentile)

Weaknesses

CVE ID

CVE-2023-43796

GHSA ID

GHSA-mp92-3jfm-3575

Source code

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