Vulnerability · Published Mar 26, 2021 · Assigned by GitHub_M
CVE-2021-21333HTML injection in email and account expiry notifications
Medium 6.1
In plain English
A medium-severity injection in synapse from matrix-org. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.4% (higher than 72% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:14 | matrix-synapse | 1.27.0-1 | DEBIAN-CVE-2021-21333 |
| PyPI | matrix-synapse | 1.27.0 | GHSA-c5f8-35qr-q4fm |
| PyPI | matrix-synapse | 1.27.0 | PYSEC-2021-134 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| matrix-org | synapse | < 1.27.0 |
Weakness: CWE-74 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N
References
- https://github.com/matrix-org/synapse/releases/tag/v1.27.0 x_refsource_MISC
- https://github.com/matrix-org/synapse/pull/9200 x_refsource_MISC
- https://github.com/matrix-org/synapse/commit/e54746bdf7d5c831eabe4dcea76a7626f1de73df x_refsource_MISC
- https://github.com/matrix-org/synapse/security/advisories/GHSA-c5f8-35qr-q4fm x_refsource_CONFIRM
- FEDORA-2021-a627cfd31e vendor-advisory, x_refsource_FEDORA