CVE-2021-29431

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.

How to fix CVE-2021-29431

To remediate CVE-2021-29431, upgrade the affected package to a fixed version below.

• —upgrade to 2.3.0 or later
• —upgrade to 3d531ed50d2fd41ac387f36d44d3fb2c62dd22d3 or later

Is CVE-2021-29431 being exploited?

Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 2.3.0
• from 0, < 3d531ed50d2fd41ac387f36d44d3fb2c62dd22d3, < 0f00412017f25619bc36c264b29ea96808bf310a, < 9e573348d81df8191bbe8c266c01999c9d57cd5f, < 8936925f561b0c352c2fa922d5097d7245aad00a | from 0, < 2.3.0

CVSS scores

References (11)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2021-29431
• PATCHgithub.com/matrix-org/sydent
• PATCHpypi.org/project/matrix-sydent/
• WEBgithub.com/matrix-org/sydent/commit/0f00412017f25619bc36c264b29ea96808bf310a