matrix-synapse is vulnerable to denial of service. A malicious homeserver is able to redirect requests to a very large .well-known
file that leads to a denial of service condition where homeservers will consume significantly more resources when requesting the malicious .well-known
file.
github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6
github.com/matrix-org/synapse/pull/8950
github.com/matrix-org/synapse/releases/tag/v1.25.0
github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8
lists.fedoraproject.org/archives/list/[email protected]/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/