CVE-2021-21274
published 2021-02-26CVE-2021-21274: Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP…
medium6.5CVSS 3.1
AVNACLPRNUIRSUCNINAH
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.
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | matrix-synapse | < matrix-synapse 1.25.0-1 (forky) | matrix-synapse 1.25.0-1 (forky) |
| fedoraproject | fedora | — | — |
| matrix-org | synapse | — | — |
| matrix | synapse | >= 0.99.0 < 1.25.0 | 1.25.0 |
CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
osv6.5MEDIUM