CVE-2023-43796

Synapse vulnerable to leak of remote user device information

MEDIUM
5.3
CVSS Score
Published: October 31, 2023 at 04:52 PM UTC
Updated: June 17, 2026 at 06:26 AM UTC
3 products affected across 3 vendorsFedoraSynapseSynapse

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.9%

Description

Synapse is an open-source Matrix homeserver Prior to versions 1.95.1 and 1.96.0rc1, cached device information of remote users can be queried from Synapse. This can be used to enumerate the remote users known to a homeserver. System administrators are encouraged to upgrade to Synapse 1.95.1 or 1.96.0rc1 to receive a patch. As a workaround, the `federation_domain_whitelist` can be used to limit federation traffic with a homeserver.

Affected

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

v < 1.95.1
Affected range stops below 1.95.1, so it looks safe — our inference, not a vendor statement
v < 1.95.1
Affected range stops below 1.95.1, 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:

CVSS

5.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-200NVD-CWE-noinfo

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