https://db.gcve.eu/rss/recent/all/10 Most recent entries from all 2026-09-29T19:34:14.241126+00:00 Vulnerability-Lookup info@gcve.eu python-feedgen Contains only the most 10 recent entries. https://db.gcve.eu/vuln/cve-2021-21333 CVE-2021-21333 — HTML injection in email and account expiry notifications 2026-09-29T19:34:14.250876+00:00

Affected: matrix-org synapse

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.