Synapse denial of service through media disk space consumption
Impact
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.
Patches
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.
Workarounds
Synapse deployments can currently decrease the maximum file size allowed, as well as increase request rate limits. However, this does not as effectively address the issue as a dedicated rate limit on remote media downloads.
Server operators may also wish to consider putting media on a dedicated disk or volume, reducing the impact of a disk fill condition.
References
For more information
If you have any questions or comments about this advisory, please email us at security at element.io.
Software afectado
Haz clic en una tecnología para ver todas sus vulnerabilidades.
| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | matrix-synapse | < 1.106 | 1.106 |
Referencias
- Vector CVSS
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Debilidad (CWE)
CWE-770- Plataforma
- Python (PyPI)
- Paquete
matrix-synapse- Publicada
- 03.12.2024
- Actualizado
- 11.10.2026 12:19
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2024-286 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-4mhg-xv73-xq2x - CC BY 4.0
Historial de vulnerabilidades: matrix-synapse
Todas las vulnerabilidades publicadas de este paquete (Python (PyPI)), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 45
- Primera → última
- 03.2019 05.2026
- Sin corrección
- 0
- Explotada en ataques
- 0
Distribución por gravedad
- Alta 21
- Media 21
- Baja 3
Divulgaciones por año
- 2019: 3
- 2020: 3
- 2021: 12
- 2022: 7
- 2023: 9
- 2024: 7
- 2025: 2
- 2026: 2
-
Synapse denial of service through media disk space consumption esta entrada
Identifica las vulnerabilidades de tu aplicación
Con la integración de DockRay y el inventario de software activado, DockRay compara las versiones notificadas de los componentes con las vulnerabilidades conocidas y avisa de las coincidencias confirmadas. La cobertura depende de la tecnología compatible y de los avisos disponibles.