CVE-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. 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.

Link	Resource
https://github.com/matrix-org/synapse/releases/tag/v1.25.0	Third Party Advisory
https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6	Patch Third Party Advisory
https://github.com/matrix-org/synapse/pull/8950	Patch Third Party Advisory
https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8	Patch Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/	Mailing List Third Party Advisory

Configuration 1

cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

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Published : 2021-02-26 06:15

Updated : 2022-10-24 08:49

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NVD link : CVE-2021-21274

Mitre link : CVE-2021-21274

No products.

CWE-770