Cross-site scripting (XSS) vulnerability in the password reset endpoint
Impact
The password reset endpoint served via Synapse was vulnerable to cross-site scripting (XSS) attacks. The impact depends on the configuration of the domain that Synapse is deployed on, but may allow access to cookies and other browser data, CSRF vulnerabilities, and access to other resources served on the same domain or parent domains.
Patches
This is fixed in #9200.
Workarounds
Depending on the needs and configuration of the homeserver a few options are available:
-
Password resets can be disabled by delegating email to a third-party service (via the
account_threepid_delegates.emailsetting) or disabling email (by not configuring theemailsetting). -
If the homeserver is not configured to use passwords (via the
password_config.enabledsetting) then the affected endpoint can be blocked at a reverse proxy:/_synapse/client/password_reset/email/submit_token
-
The
password_reset_confirmation.htmltemplate can be overridden with a custom template that manually escapes the variables using JInja2'sescapefilter. See theemail.template_dirsetting.
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | matrix-synapse | < 1.27.0 | 1.27.0 |
Referencias
- https://github.com/matrix-org/synapse/pull/9200
- https://github.com/matrix-org/synapse/commit/e54746bdf7d5c831eabe4dcea76a7626f1de73df
- https://github.com/matrix-org/synapse/security/advisories/GHSA-246w-56m2-5899
- https://github.com/matrix-org/synapse/releases/tag/v1.27.0
- https://nvd.nist.gov/vuln/detail/CVE-2021-21332
- https://github.com/matrix-org/synapse
- https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2021-133.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:C/C:H/I:L/A:N- Debilidad (CWE)
CWE-79- Plataforma
- Python (PyPI)
- Paquete
matrix-synapse- Publicada
- 26.03.2021
- Actualizado
- 11.10.2026 13:19
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2021-133 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-246w-56m2-5899 - 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
-
Cross-site scripting (XSS) vulnerability in the password reset endpoint esta entrada
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