CVE-2021-29430

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.

Risk Information

Base Score

7.5

MODERATE

Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Score

Exploitation Probability

1.367

Associated Vulnerability

Vulnerability	OS Platform
Vulnerabilities CVE-2021-29430,CVE-2021-29431,CVE-2021-29432,CVE-2021-29433 are fixed in Python-matrix-sydent 2.3.0	Windows
Vulnerabilities CVE-2021-29430,CVE-2021-29431,CVE-2021-29432,CVE-2021-29433 are fixed in Python-matrix-sydent for linux 2.3.0	Linux

Patch Details

No records found

References

https://nvd.nist.gov/vuln/detail/CVE-2023-1234
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1234