CVE-2021-21332

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 password reset endpoint served via Synapse was vulnerable to cross-site scripting (XSS) attacks. The impact depends on the configuration of the domain that Synapse is deployed on, but may allow access to cookies and other browser data, CSRF vulnerabilities, and access to other resources served on the same domain or parent domains. This is fixed in version 1.27.0.

How to fix CVE-2021-21332

To remediate CVE-2021-21332, upgrade the affected package to a fixed version below.

• —upgrade to 1.27.0-1 or later
• —upgrade to 1.27.0 or later
• —upgrade to e54746bdf7d5c831eabe4dcea76a7626f1de73df or later

Is CVE-2021-21332 being exploited?

Low — EPSS is 0.5%, meaning exploitation activity has not been observed at scale.

Affected packages (3)

• from 0, < 1.27.0-1
• from 0, < 1.27.0
• from 0, < e54746bdf7d5c831eabe4dcea76a7626f1de73df | from 0, < 1.27.0

CVSS scores

References (9)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2021-21332
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2021-21332
• PATCHgithub.com/matrix-org/synapse
• WEBgithub.com/matrix-org/synapse/commit/e54746bdf7d5c831eabe4dcea76a7626f1de73df
• WEB