Candidate: CVE-2021-21333
PublicDate: 2021-03-26 20:15:00 UTC
References:
 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21333
 https://github.com/matrix-org/synapse/commit/e54746bdf7d5c831eabe4dcea76a7626f1de73df
 https://github.com/matrix-org/synapse/pull/9200
 https://github.com/matrix-org/synapse/releases/tag/v1.27.0
 https://github.com/matrix-org/synapse/security/advisories/GHSA-c5f8-35qr-q4fm
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.
Ubuntu-Description:
Notes:
Mitigation:
Bugs:
 https://github.com/matrix-org/synapse/pull/9200
Priority: low
Discovered-by:
Assigned-to:
CVSS:
 nvd: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N [6.1 MEDIUM]


Patches_matrix-synapse:
upstream_matrix-synapse: released (1.27.0-1)
precise/esm_matrix-synapse: DNE
trusty_matrix-synapse: ignored (out of standard support)
trusty/esm_matrix-synapse: DNE
xenial_matrix-synapse: DNE
bionic_matrix-synapse: needs-triage
focal_matrix-synapse: needs-triage
groovy_matrix-synapse: ignored (reached end-of-life)
hirsute_matrix-synapse: not-affected (1.27.0-1)
impish_matrix-synapse: not-affected (1.27.0-1)
jammy_matrix-synapse: not-affected (1.27.0-1)
devel_matrix-synapse: not-affected (1.27.0-1)