Vulnerability Description
Sydent is a reference Matrix identity server. Sydent does not limit the size of requests it receives from HTTP clients. A malicious user could send an HTTP request with a very large body, leading to memory exhaustion and denial of service. Sydent also does not limit response size for requests it makes to remote Matrix homeservers. A malicious homeserver could return a very large response, again leading to memory exhaustion and denial of service. This affects any server which accepts registration requests from untrusted clients. This issue has been patched by releases 89071a1, 0523511, f56eee3. As a workaround request sizes can be limited in an HTTP reverse-proxy. There are no known workarounds for the problem with overlarge responses.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Matrix | Sydent | < 2.3.0 |
Related Weaknesses (CWE)
References
- https://github.com/matrix-org/sydent/commit/0523511d2fb40f2738f8a8549868f44b96e5PatchThird Party Advisory
- https://github.com/matrix-org/sydent/commit/89071a1a754c69a50deac89e6bb74002d4cdPatchThird Party Advisory
- https://github.com/matrix-org/sydent/commit/f56eee315b6c44fdd9f6aa785cc2ec744a59PatchThird 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-wmg4-8cp2-hpg9PatchThird Party Advisory
- https://pypi.org/project/matrix-sydent/ProductThird Party Advisory
- https://github.com/matrix-org/sydent/commit/0523511d2fb40f2738f8a8549868f44b96e5PatchThird Party Advisory
- https://github.com/matrix-org/sydent/commit/89071a1a754c69a50deac89e6bb74002d4cdPatchThird Party Advisory
- https://github.com/matrix-org/sydent/commit/f56eee315b6c44fdd9f6aa785cc2ec744a59PatchThird 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-wmg4-8cp2-hpg9PatchThird Party Advisory
- https://pypi.org/project/matrix-sydent/ProductThird Party Advisory
FAQ
What is CVE-2021-29430?
CVE-2021-29430 is a vulnerability with a CVSS score of 7.5 (HIGH). Sydent is a reference Matrix identity server. Sydent does not limit the size of requests it receives from HTTP clients. A malicious user could send an HTTP request with a very large body, leading to m...
How severe is CVE-2021-29430?
CVE-2021-29430 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-29430?
Check the references section above for vendor advisories and patch information. Affected products include: Matrix Sydent.