Detections
Analytics

CVE-2021-29431

medium

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.

References

https://pypi.org/project/matrix-sydent/

https://github.com/matrix-org/sydent/security/advisories/GHSA-9jhm-8m8c-c3f4

https://github.com/matrix-org/sydent/releases/tag/v2.3.0

https://github.com/matrix-org/sydent/commit/9e573348d81df8191bbe8c266c01999c9d57cd5f

https://github.com/matrix-org/sydent/commit/8936925f561b0c352c2fa922d5097d7245aad00a

https://github.com/matrix-org/sydent/commit/3d531ed50d2fd41ac387f36d44d3fb2c62dd22d3

https://github.com/matrix-org/sydent/commit/0f00412017f25619bc36c264b29ea96808bf310a

Details

Source: Mitre, NVD

Published: 2021-04-15

Updated: 2026-06-17

Risk Information

CVSS v2

Base Score: 4

Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:N/A:N

Severity: Medium

CVSS v3

Base Score: 6.5

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

Severity: Medium

CVSS v4

Base Score: 6.3

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N

Severity: Medium

EPSS

EPSS: 0.00303