Home/CVE/Sydent is a reference Matrix identity server. Sydent can be induced to send HTTP GET requests to internal systems, due t
CVE

CVE-2021-29431

Sydent is a reference Matrix identity server. Sydent can be induced to send HTTP GET requests to internal systems, due t

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 9e57334, 8936925, 3d531ed, 0f00412. A potential workaround would be to use a firewall to ensure that Sydent cannot reach internal HTTP resources.

HIGH · CVSS 7.7 EPSS 0.00303
Schedule remediation
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-20Improper Input Validation
CWE-918Server-Side Request Forgery (SSRF)
▤

Affected Products & Versions

1
matrix sydent< 2.3.0
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
PyPI matrix-sydent MODERATE fixed in 2.3.0
▣

Scoring & Timeline

7.7
HIGH · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD15 Apr 2021 · 09:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
🔗

References & Sources

7
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/matrix-org/sydent/commit/0f00412017f25619bc36c264b29ea96808bf310aPatchThird Party Advisory
https://github.com/matrix-org/sydent/commit/3d531ed50d2fd41ac387f36d44d3fb2c62dd22d3PatchThird Party Advisory
https://github.com/matrix-org/sydent/commit/8936925f561b0c352c2fa922d5097d7245aad00aPatchThird Party Advisory
https://github.com/matrix-org/sydent/commit/9e573348d81df8191bbe8c266c01999c9d57cd5fPatchThird Party Advisory
https://github.com/matrix-org/sydent/releases/tag/v2.3.0Release NotesThird Party Advisory
https://github.com/matrix-org/sydent/security/advisories/GHSA-9jhm-8m8c-c3f4PatchThird Party Advisory
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