cvedb.io
CVE-2021-41281
HIGH · CVSS 7.5
EPSS exploitation probability: 0%
Published 2021-11-23T20:15:11.687 · Last modified 2026-06-17T04:08:14.110

Summary

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 m

Affected products

matrix — synapse

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.