Synapse is a package for Matrix homeservers written in Python 3/Twisted. Prior to version 1.47.1, Synapse instances with the media repository enabled can be tricked into downloading a file from a remote server into an arbitrary directory. No authentication is required for the affected endpoint. The last 2 directories and file name of the path are chosen randomly by Synapse and cannot be controlled by an attacker, which limits the impact. Homeservers with the media repository disabled are unaffected. Homeservers with a federation whitelist are also unaffected, since Synapse will check the remote hostname, including the trailing `../`s, against the whitelist. Server administrators should upgrade to 1.47.1 or later. Server administrators using a reverse proxy could, at the expense of losing media functionality, may block the certain endpoints as a workaround. Alternatively, non-containerized deployments can be adapted to use the hardened systemd config.
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cve-icon MITRE Information

Status: PUBLISHED

Assigner: GitHub_M

Published: 2021-11-23T19:15:18

Updated: 2021-12-09T02:06:11

Reserved: 2021-09-15T00:00:00


Link: CVE-2021-41281

JSON object: View

cve-icon NVD Information

Status : Modified

Published: 2021-11-23T20:15:11.687

Modified: 2023-11-07T03:38:54.953


Link: CVE-2021-41281

JSON object: View

cve-icon Redhat Information

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CWE