CVE-2023-32323
low-risk
Published 2023-05-26
Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. A malicious user on a Synapse homeserver X with permission to create certain state events can disable outbound federation from X to an arbitrary homeserver Y. Synapse instances with federation disabled are not affected. In versions of Synapse up to and including 1.73, Synapse did not limit the size of `invite_room_state`, meaning that it was possible to create an arbitrarily large invite event. Synapse 1.74 refuses to create oversized `invite_room_state` fields. Server operators should upgrade to Synapse 1.74 or newer urgently.
Do I need to act?
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0.14% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
5
CVSS 5.0/10
Medium
NETWORK
/ LOW complexity
Affected Products (1)
Affected Vendors
References (8)
26
/ 100
low-risk
Severity
20/34 · Moderate
Exploitability
1/34 · Minimal
Exposure
5/34 · Minimal