VYPR
Moderate severityNVD Advisory· Published May 26, 2023· Updated Feb 13, 2025

Synapse Outgoing federation to specific hosts can be disabled by sending malicious invites

CVE-2023-32323

Description

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.

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Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
matrix-synapsePyPI
< 1.74.01.74.0

Affected products

2

Patches

Vulnerability mechanics

References

8

News mentions

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