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 1.27.0, the notification emails sent for notifications for missed messages or for an expiring account are subject to HTML injection. In the case of the notification for missed messages, this could allow an attacker to insert forged content into the email. The account expiry feature is not enabled by default and the HTML injection is not controllable by an attacker. This is fixed in version 1.27.0.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Matrix | Synapse | < 1.27.0 |
| Fedoraproject | Fedora | 34 |
Related Weaknesses (CWE)
References
- https://github.com/matrix-org/synapse/commit/e54746bdf7d5c831eabe4dcea76a7626f1dPatchThird Party Advisory
- https://github.com/matrix-org/synapse/pull/9200PatchThird Party Advisory
- https://github.com/matrix-org/synapse/releases/tag/v1.27.0Third Party Advisory
- https://github.com/matrix-org/synapse/security/advisories/GHSA-c5f8-35qr-q4fmPatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://github.com/matrix-org/synapse/commit/e54746bdf7d5c831eabe4dcea76a7626f1dPatchThird Party Advisory
- https://github.com/matrix-org/synapse/pull/9200PatchThird Party Advisory
- https://github.com/matrix-org/synapse/releases/tag/v1.27.0Third Party Advisory
- https://github.com/matrix-org/synapse/security/advisories/GHSA-c5f8-35qr-q4fmPatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
FAQ
What is CVE-2021-21333?
CVE-2021-21333 is a vulnerability with a CVSS score of 6.1 (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 1.27.0, the no...
How severe is CVE-2021-21333?
CVE-2021-21333 has been rated MEDIUM with a CVSS base score of 6.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-21333?
Check the references section above for vendor advisories and patch information. Affected products include: Matrix Synapse, Fedoraproject Fedora.