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.

Predictions

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No vendor mitigations ingested yet for this CVE. The mitigation-content worker queues fetches as references arrive — check back in a few minutes, or see the references list below.

References

• https://github.com/matrix-org/sydent/security/advisories/GHSA-9jhm-8m8c-c3f4
• https://nvd.nist.gov/vuln/detail/CVE-2021-29431
• https://github.com/matrix-org/sydent/commit/0f00412017f25619bc36c264b29ea96808bf310a
• https://github.com/matrix-org/sydent/commit/3d531ed50d2fd41ac387f36d44d3fb2c62dd22d3
• https://github.com/matrix-org/sydent/commit/8936925f561b0c352c2fa922d5097d7245aad00a
• https://github.com/matrix-org/sydent/commit/9e573348d81df8191bbe8c266c01999c9d57cd5f
• https://github.com/matrix-org/sydent
• https://github.com/matrix-org/sydent/releases/tag/v2.3.0
• https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-22.yaml
• https://pypi.org/project/matrix-sydent
• https://pypi.org/project/matrix-sydent/