CVE-2021-21332
moderate-risk
Published 2021-03-26
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.
Do I need to act?
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0.51% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
6
CVSS 6.9/10
Medium
NETWORK
/ HIGH complexity
Affected Vendors
References (10)
Third Party Advisory
https://github.com/matrix-org/synapse/releases/tag/v1.27.0
Third Party Advisory
https://github.com/matrix-org/synapse/security/advisories/GHSA-246w-56m2-5899
Third Party Advisory
https://github.com/matrix-org/synapse/releases/tag/v1.27.0
Third Party Advisory
https://github.com/matrix-org/synapse/security/advisories/GHSA-246w-56m2-5899
30
/ 100
moderate-risk
Severity
21/34 · High
Exploitability
2/34 · Minimal
Exposure
7/34 · Low