CVE-2021-21274

 

Published at: - 26-02-2021 07:15

Last modified: - 24-10-2022 10:49

Total changes: - 5

Description

Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.25.0, a malicious homeserver could redirect requests to their .well-known file to a large file. This can lead to a denial of service attack where homeservers will consume significantly more resources when requesting the .well-known file of a malicious homeserver. This affects any server which accepts federation requests from untrusted servers. Issue is resolved in version 1.25.0. As a workaround the `federation_domain_whitelist` setting can be used to restrict the homeservers communicated with over federation.

Common Vulnerability Scoring System (CVSS)

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

 

Verification logic

 

Reference

• https://github.com/matrix-org/synapse/releases/tag/v1.25.0
• https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6
• https://github.com/matrix-org/synapse/pull/8950
• https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8
• FEDORA-2021-a627cfd31e-Mailing List, Third Party Advisory

 

Keywords

NVD

 

CVE-2021-21274

 

CVE

 

Common vulnerabilities & exposures

 

CVSS

 

Common vulnerability scoring system

 

Security

 

Vulnerabilities

 

Exposures