# CVE-2024-37302: matrix-synapse: Synapse is an open-source Matrix homeserver

CVE-2024-37302 is fixed in matrix-synapse on 1 platform by DEBIAN-CVE-2024-37302 (version 1.116.0-1), released December 3, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2024-37302
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0060
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 3, 2024

## Description

Synapse is an open-source Matrix homeserver. Synapse versions before 1.106 are vulnerable to a disk fill attack, where an unauthenticated adversary can induce Synapse to download and cache large amounts of remote media. The default rate limit strategy is insufficient to mitigate this. This can lead to a denial of service, ranging from further media uploads/downloads failing to completely unavailability of the Synapse process, depending on how Synapse was deployed. Synapse 1.106 introduces a new "leaky bucket" rate limit on remote media downloads to reduce the amount of data a user can request at a time. This does not fully address the issue, but does limit an unauthenticated user's ability to request large amounts of data to be cached.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | matrix-synapse Debian 14 | 1.116.0-1 | [DEBIAN-CVE-2024-37302](https://patchblox.com/security/data/fix/linux/debian-cve-2024-37302.md) | Dec 3, 2024 |

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Data as of 2026-11-08T13:06:02Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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