CVE-2021-21333
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2021-21333
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| debian | forky | fixed | 1.27.0-1 |
| debian | sid | fixed | 1.27.0-1 |
Package impact
| Ecosystem | Package | Vulnerable | Fixed |
|---|---|---|---|
| PyPI | matrix-synapse | <1.27.0 | 1.27.0 |
| PyPI | matrix-synapse | <e54746bdf7d5c831eabe4dcea76a7626f1de73df||<1.27.0 | e54746bdf7d5c831eabe4dcea76a7626f1de73df |
References
- https://github.com/matrix-org/synapse/security/advisories/GHSA-c5f8-35qr-q4fm
- https://nvd.nist.gov/vuln/detail/CVE-2021-21333
- https://github.com/matrix-org/synapse/pull/9200
- https://github.com/matrix-org/synapse/commit/e54746bdf7d5c831eabe4dcea76a7626f1de73df
- https://github.com/matrix-org/synapse
- https://github.com/matrix-org/synapse/releases/tag/v1.27.0
- https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2021-134.yaml
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY
- https://security-tracker.debian.org/tracker/CVE-2021-21333
Verify integrity in audit chain (admin only). AS-IS.