CVE-2021-21333

medium

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.

References

Advisories

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/

https://github.com/matrix-org/synapse/security/advisories/GHSA-c5f8-35qr-q4fm

https://github.com/matrix-org/synapse/releases/tag/v1.27.0

https://github.com/matrix-org/synapse/pull/9200

https://github.com/matrix-org/synapse/commit/e54746bdf7d5c831eabe4dcea76a7626f1de73df

Details

Source: Mitre, NVD

Published: 2021-03-26

Updated: 2024-11-21

Risk Information

CVSS v2

Base Score: 2.6

Vector: CVSS2#AV:N/AC:H/Au:N/C:N/I:P/A:N

Severity: Low

CVSS v3

Base Score: 6.1

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N

Severity: Medium

CVSS v4

Base Score: 4.9

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:N/SI:H/SA:N

Severity: Medium

EPSS

EPSS: 0.00538