CVE-2021-29431
7.7 · HIGHOverview
CVE-2021-29431 is a high-severity vulnerability affecting matrix sydent. It was published on April 15, 2021 and has a CVSS 3.1 base score of 7.7 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.7, rated HIGH. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical Description
Sydent is a reference Matrix identity server. Sydent can be induced to send HTTP GET requests to internal systems, due to lack of parameter validation or IP address blacklisting. It is not possible to exfiltrate data or control request headers, but it might be possible to use the attack to perform an internal port enumeration. This issue has been addressed in in 9e57334, 8936925, 3d531ed, 0f00412. A potential workaround would be to use a firewall to ensure that Sydent cannot reach internal HTTP resources.
Remediation
Check the references section for vendor advisories and patches from matrix. Update sydent to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| matrix | sydent | >= 0, < 2.3.0 | Affected |
References
Frequently Asked Questions
What is CVE-2021-29431?
CVE-2021-29431 is a high-severity vulnerability affecting matrix sydent. It was published on April 15, 2021 and has a CVSS 3.1 base score of 7.7 (HIGH).
How severe is CVE-2021-29431?
This vulnerability has a CVSS 3.1 base score of 7.7, rated HIGH. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2021-29431?
Check the references section for vendor advisories and patches from matrix. Update sydent to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-29431?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-29431 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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