Vulnerability Description
Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.28.0 requests to user provided domains were not restricted to external IP addresses when transitional IPv6 addresses were used. Outbound requests to federation, identity servers, when calculating the key validity for third-party invite events, sending push notifications, and generating URL previews are affected. This could cause Synapse to make requests to internal infrastructure on dual-stack networks. See referenced GitHub security advisory for details and workarounds.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Matrix | Synapse | < 1.28.0 |
| Fedoraproject | Fedora | 34 |
Related Weaknesses (CWE)
References
- https://github.com/matrix-org/synapse/pull/9240PatchThird Party Advisory
- https://github.com/matrix-org/synapse/security/advisories/GHSA-5wrh-4jwv-5w78PatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://pypi.org/project/matrix-synapse/ProductThird Party Advisory
- https://github.com/matrix-org/synapse/pull/9240PatchThird Party Advisory
- https://github.com/matrix-org/synapse/security/advisories/GHSA-5wrh-4jwv-5w78PatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://pypi.org/project/matrix-synapse/ProductThird Party Advisory
FAQ
What is CVE-2021-21392?
CVE-2021-21392 is a vulnerability with a CVSS score of 6.3 (MEDIUM). Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.28.0 request...
How severe is CVE-2021-21392?
CVE-2021-21392 has been rated MEDIUM with a CVSS base score of 6.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-21392?
Check the references section above for vendor advisories and patch information. Affected products include: Matrix Synapse, Fedoraproject Fedora.