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CVE-2021-41281 Detail

Description

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.


Severity



CVSS 4.0 Severity and Metrics:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.


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Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/matrix-org/synapse/commit/91f2bd090 Patch  Third Party Advisory 
https://github.com/matrix-org/synapse/releases/tag/v1.47.1 Release Notes  Third Party Advisory 
https://github.com/matrix-org/synapse/security/advisories/GHSA-3hfw-x7gx-437c Mitigation  Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EU7QRE55U4IUEDLKT5IYPWL3UXMELFAS/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/N3WY56LCEZ4ZECLWV5KMAXF2PSMUB4F2/

Weakness Enumeration

CWE-ID CWE Name Source
CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') cwe source acceptance level NIST   Contributor acceptance level GitHub, Inc.  

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Change History

5 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-41281
NVD Published Date:
11/23/2021
NVD Last Modified:
11/06/2023
Source:
GitHub, Inc.