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CVE-2021-29430

CVE information

Published

3 years ago

Last Modified

1 year ago

CVSSv2.0 Severity

Medium

CVSSv3.1 Severity

High

Impact Analysis

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..

CVSSv2.0 Score

Severity
Medium
Base Score
5/10
Exploit Score
10/10
Access Vector
Network
Access Complexity
Low
Authentication Required
None
Impact Score
2.9/10
Confidentiality Impact
None
Availability Impact
Partial
Integrity Impact
None

CVSSv3.1 Score

Severity
High
Base Score
7.5/10
Exploit Score
3.9/10
Access Vector
Network
Access Complexity
Low
Privileges Required
None
Impact Score
3.6/10
Confidentiality Impact
None
Availability Impact
High
Integrity Impact
None
Scope
Unchanged
User Interaction
None

Products Affected

CPE Affected Vulnerable Excluding Edit
cpe:2.3:a:matrix:sydent:*:*:*:*:*:*:*:*
  Yes
- 2.3.0