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 disk space 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.
Patched by 89071a1, 0523511, f56eee3.
Request sizes can be limited in an HTTP reverse-proxy.
There are no known workarounds for the problem with overlarge responses.
If you have any questions or comments about this advisory, email us at [email protected].
CPE | Name | Operator | Version |
---|---|---|---|
matrix-sydent | eq | 2.1.0 | |
matrix-sydent | eq | 2.2.0 | |
matrix-sydent | eq | 2.0.1 | |
matrix-sydent | eq | 2.0.0 |
github.com/matrix-org/sydent/commit/0523511d2fb40f2738f8a8549868f44b96e5dab7
github.com/matrix-org/sydent/commit/89071a1a754c69a50deac89e6bb74002d4cda19d
github.com/matrix-org/sydent/commit/f56eee315b6c44fdd9f6aa785cc2ec744a594428
github.com/matrix-org/sydent/releases/tag/v2.3.0
github.com/matrix-org/sydent/security/advisories/GHSA-wmg4-8cp2-hpg9
nvd.nist.gov/vuln/detail/CVE-2021-29430
pypi.org/project/matrix-sydent