# CVE-2023-32323: matrix-synapse: Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation

CVE-2023-32323 is fixed in matrix-synapse on 1 platform by DEBIAN-CVE-2023-32323 (version 1.74.0-1), released May 26, 2023. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2023-32323
- Priority: Routine
- CVSS: 4.3 (medium)
- EPSS: 0.0098
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 26, 2023

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | matrix-synapse Debian 14 | 1.74.0-1 | [DEBIAN-CVE-2023-32323](https://patchblox.com/security/data/fix/linux/debian-cve-2023-32323.md) | May 26, 2023 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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