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CVE-2021-29431

7.7 · HIGH

Sydent is a reference Matrix identity server.

Published Apr 15, 2021CWE-20EPSS 1.19%

Overview

CVE-2021-29431 is a high-severity vulnerability. 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, patches, and mitigation guidance. 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.

References

GitHubgithub.com/matrix-org/sydent/commit/0f00412017f25619bc36c264b29ea96808bf310aGitHubgithub.com/matrix-org/sydent/commit/3d531ed50d2fd41ac387f36d44d3fb2c62dd22d3GitHubgithub.com/matrix-org/sydent/commit/8936925f561b0c352c2fa922d5097d7245aad00aGitHubgithub.com/matrix-org/sydent/commit/9e573348d81df8191bbe8c266c01999c9d57cd5fGitHubgithub.com/matrix-org/sydent/releases/tag/v2.3.0GitHubgithub.com/matrix-org/sydent/security/advisories/GHSA-9jhm-8m8c-c3f4Refpypi.org/project/matrix-sydent/GitHubgithub.com/matrix-org/sydent/commit/0f00412017f25619bc36c264b29ea96808bf310aGitHubgithub.com/matrix-org/sydent/commit/3d531ed50d2fd41ac387f36d44d3fb2c62dd22d3GitHubgithub.com/matrix-org/sydent/commit/8936925f561b0c352c2fa922d5097d7245aad00a

How CyberStrike helps

Frequently asked questions

What is CVE-2021-29431?

CVE-2021-29431 is a high-severity vulnerability. 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, patches, and mitigation guidance. 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 is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-29431 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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