Vulnerability · Published Apr 15, 2021 · Assigned by GitHub_M
CVE-2021-29430Denial of service attack via memory exhaustion
High 7.5
In plain English
A high-severity improper input validation in sydent from matrix-org. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.8% (higher than 79% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | matrix-sydent | 2.3.0 | GHSA-wmg4-8cp2-hpg9 |
| PyPI | matrix-sydent | 2.3.0 | PYSEC-2021-21 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| matrix-org | sydent | < 2.3.0 |
Weakness: CWE-20, CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://pypi.org/project/matrix-sydent/ x_refsource_MISC
- https://github.com/matrix-org/sydent/security/advisories/GHSA-wmg4-8cp2-hpg9 x_refsource_CONFIRM
- https://github.com/matrix-org/sydent/commit/89071a1a754c69a50deac89e6bb74002d4cda19d x_refsource_MISC
- https://github.com/matrix-org/sydent/commit/0523511d2fb40f2738f8a8549868f44b96e5dab7 x_refsource_MISC
- https://github.com/matrix-org/sydent/commit/f56eee315b6c44fdd9f6aa785cc2ec744a594428 x_refsource_MISC
- https://github.com/matrix-org/sydent/releases/tag/v2.3.0 x_refsource_MISC