6.5

CVE-2021-21274

Denial of service attack via .well-known lookups

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.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Matrix ≫ Synapse Version >= 0.99.0 < 1.25.0
Fedoraproject ≫ Fedora Version34
Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 2.16% 0.799
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 6.5 2.8 3.6
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
nvd@nist.gov 4.3 8.6 2.9
AV:N/AC:M/Au:N/C:N/I:N/A:P
security-advisories@github.com 4.3 2.8 1.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
CWE-400 Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource.

CWE-770 Allocation of Resources Without Limits or Throttling

The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

https://github.com/matrix-org/synapse/releases/tag/v1.25.0
Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/
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