https://cve.radiocsirt.org/rss/recent/all/10 Most recent entries from all 2026-10-21T16:52:49.607541+00:00 Vulnerability-Lookup csirt@opendfir.org python-feedgen Contains only the most 10 recent entries. https://cve.radiocsirt.org/vuln/euvd-2026-216478 EUVD-2026-216478 2026-10-21T16:52:49.611891+00:00 EUVD-2026-216478 https://cve.radiocsirt.org/vuln/fkie_cve-2023-32323 fkie_cve-2023-32323 2026-10-21T16:52:49.611946+00:00

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.

 https://cve.radiocsirt.org/vuln/ghsa-f3wc-3vxv-xmvr GHSA-f3wc-3vxv-xmvr — Synapse Outgoing federation to specific hosts can be disabled by sending malicious invites 2026-10-21T16:52:49.612031+00:00

Affected: PyPI: matrix-synapse

### Impact

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.

#### Details

The Matrix protocol allows homeservers to provide an `invite_room_state` field on a [room invite](https://spec.matrix.org/v1.5/client-server-api/#mroommember) containing a [summary of room state](https://spec.matrix.org/v1.5/client-server-api/#stripped-state). In versions of Synapse up to and including v1.73.0, Synapse did not limit the size of `invite_room_state`, meaning that it was possible to create an arbitrarily large invite event.

An attacker with an account on a vulnerable Synapse homeserver X could exploit this by having X create an over-sized invite event in a room with a user from another homeserver Y. Once acknowledged by the invitee's homeserver, the invite event would be sent in a batch of events to Y. If the malicious invite is so large that the entire batch is rejected as too large, X's outgoing traffic to Y would become "stuck", meaning that messages and state events created by X would remain unseen by Y.

### Patches

Synapse 1.74 refuses to create oversized `invite_room_state` fields. Server operators should upgrade to Synapse 1.74 or newer urgently.

### Workarounds

There are no robust workarounds.

This attack needs an account on Synapse homeserver X to deny federation from X to another homeserver Y. As a pa…

 https://cve.radiocsirt.org/vuln/gsd-2023-32323 gsd-2023-32323 2026-10-21T16:52:49.612115+00:00 gsd-2023-32323 https://cve.radiocsirt.org/vuln/pysec-2023-67 PYSEC-2023-67 2026-10-21T16:52:49.612146+00:00

Affected: PyPI: matrix-synapse

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.

 https://cve.radiocsirt.org/vuln/ubuntu-cve-2023-32323 UBUNTU-CVE-2023-32323 2026-10-21T16:52:49.612201+00:00

Affected: Ubuntu:Pro:18.04:LTS: matrix-synapse, Ubuntu:Pro:20.04:LTS: matrix-synapse, Ubuntu:22.04:LTS: matrix-synapse

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.