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.
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Affected Vendors & Products
References
History
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2024-08-03T18:09:15.070Z
Reserved: 2020-12-22T00:00:00
Link: CVE-2021-21274
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Status : Modified
Published: 2021-02-26T18:15:12.237
Modified: 2024-11-21T05:47:54.520
Link: CVE-2021-21274
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