Open redirects on some federation and push requests
Impact
Requests to user provided domains were not restricted to external IP addresses when calculating the key validity for third-party invite events and sending push notifications. This could cause Synapse to make requests to internal infrastructure. The type of request was not controlled by the user, although limited modification of request bodies was possible.
For the most thorough protection server administrators should remove the deprecated federation_ip_range_blacklist from their settings after upgrading to Synapse v1.25.0 which will result in Synapse using the improved default IP address restrictions. See the new ip_range_blacklist and ip_range_whitelist settings if more specific control is necessary.
Patches
Issue is resolved by #8821. Further improvements to protect homeservers by default were made in #8870 and #8954.
Workarounds
Requests to internal IP addresses could be blocked at the system or network level.
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | matrix-synapse | < 1.25.0 | 1.25.0 |
Referencias
- https://github.com/matrix-org/synapse/releases/tag/v1.25.0
- https://github.com/matrix-org/synapse/commit/30fba6210834a4ecd91badf0c8f3eb278b72e746
- https://github.com/matrix-org/synapse/security/advisories/GHSA-v936-j8gp-9q3p
- https://github.com/matrix-org/synapse/pull/8821
- https://nvd.nist.gov/vuln/detail/CVE-2021-21273
- https://github.com/matrix-org/synapse
- https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2021-131.yaml
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY
- Vector CVSS
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N- Debilidad (CWE)
CWE-601- Plataforma
- Python (PyPI)
- Paquete
matrix-synapse- Publicada
- 26.02.2021
- Actualizado
- 11.10.2026 13:19
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2021-131 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-v936-j8gp-9q3p - 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
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Open redirects on some federation and push requests esta entrada
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