Synapse can be forced to thumbnail unexpected file formats, invoking external, potentially untrustworthy decoders
Impact
In Synapse versions before 1.120.1, enabling the dynamic_thumbnails option or processing a specially crafted request could trigger the decoding and thumbnail generation of uncommon image formats, potentially invoking external tools like Ghostscript for processing.
This significantly expands the attack surface in a historically vulnerable area, presenting a risk that far outweighs the benefit, particularly since these formats are rarely used on the open web or within the Matrix ecosystem.
For a list of image formats, as well as decoding libraries and helper programs used, see the Pillow documentation.
Patches
Synapse 1.120.1 addresses the issue by restricting thumbnail generation to images in the following widely used formats: PNG, JPEG, GIF, and WebP.
Workarounds
- Ensure any image codecs and helper programs, such as Ghostscript, are patched against security vulnerabilities.
- Uninstall unused image decoder libraries and helper programs, such as Ghostscript, from the system environment that Synapse is running in.
- Depending on the installation method, there may be some decoder libraries bundled with Pillow and these cannot be easily uninstalled.
- The official Docker container image does not include Ghostscript.
References
- The Pillow documentation includes a list of supported image formats and which libraries or helper programs are used to decode them.
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 | < 1.120.1 | 1.120.1 |
Referencias
- Vector CVSS
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X- Debilidad (CWE)
CWE-434- Plataforma
- Python (PyPI)
- Paquete
matrix-synapse- Publicada
- 03.12.2024
- Actualizado
- 11.10.2026 13:18
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2026-1615 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-vp6v-whfm-rv3g - 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 can be forced to thumbnail unexpected file formats, invoking external, potentially untrustworthy decoders 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.