http://bugzilla.opensuse.org/show_bug.cgi?id=1182895 Bug ID: 1182895 Summary: VUL-0: CVE-2021-21274: matrix-synapse: malicious homeserver could redirect requests to their .well-known file to a large file Classification: openSUSE Product: openSUSE Distribution Version: Leap 15.2 Hardware: Other URL: https://smash.suse.de/issue/278710/ OS: Other Status: NEW Severity: Minor Priority: P5 - None Component: Basesystem Assignee: okurz@suse.com Reporter: abergmann@suse.com QA Contact: security-team@suse.de Found By: Security Response Team Blocker: --- 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. References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-21274 https://github.com/matrix-org/synapse/releases/tag/v1.25.0 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21274 https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771b... https://github.com/matrix-org/synapse/pull/8950 https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g... -- You are receiving this mail because: You are on the CC list for the bug.