Denial of service attack due to invalid JSON
Impact
A denial of service attack against Matrix clients can be exploited by sending an event including invalid JSON data to Synapse. Synapse would relay the data to clients which could crash or hang. Impact is long-lasting if the event is made part of the room state.
Patches
At a minimum #8106 and #8291 must be applied. #7372 and #8124 include additional checks.
Workarounds
There are no known workarounds.
Upgrading notes
If an invalid event is accepted by an earlier Synapse it can become part of the room state and will not be fixed by upgrading Synapse. Redacting the invalid event should avoid clients receiving the invalid event.
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | matrix-synapse | < 1.20.0 | 1.20.0 |
Referencias
- https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U34DPP4ZLOEDUY2ZCWOHQPU5GA5LYNUQ/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/G7YXMMYQP46PYL664JQUXCA3LPBJU7DQ/
- https://nvd.nist.gov/vuln/detail/CVE-2020-26890
- https://github.com/matrix-org/synapse
- https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2020-237.yaml
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/G7YXMMYQP46PYL664JQUXCA3LPBJU7DQ
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U34DPP4ZLOEDUY2ZCWOHQPU5GA5LYNUQ
- https://pypi.org/project/matrix-synapse
- Vector CVSS
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Debilidad (CWE)
CWE-20- Plataforma
- Python (PyPI)
- Paquete
matrix-synapse- Publicada
- 24.11.2020
- Actualizado
- 11.10.2026 13:19
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2020-237 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-4mp3-385r-v63f - 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
-
Denial of service attack due to invalid JSON esta entrada
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