CVE-2021-29431 HIGH

CVE-2021-29431: SSRF in Sydent due to missing validation of hostnames

Vendor Matrix-Org
Product sydent
Weakness CWE-20 · Input validation
Published April 15, 2021
Last update August 3, 2024

CVSS base score

7.7/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality High
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

April 15, 2021 CVE published
August 3, 2024 Record updated