CVE-2024-37303

Publication date 3 December 2024

Last updated 11 July 2025

Ubuntu priority

Cvss 3 Severity Score

Synapse is an open-source Matrix homeserver. Synapse before version 1.106 allows, by design, unauthenticated remote participants to trigger a download and caching of remote media from a remote homeserver to the local media repository. Such content then also becomes available for download from the local homeserver in an unauthenticated way. The implication is that unauthenticated remote adversaries can use this functionality to plant problematic content into the media repository. Synapse 1.106 introduces a partial mitigation in the form of new endpoints which require authentication for media downloads. The unauthenticated endpoints will be frozen in a future release, closing the attack vector.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
matrix-synapse	24.10 oracular	Ignored end of life, was deferred [7/4/2025]
	24.04 LTS noble	Vulnerable, fix deferred
	22.04 LTS jammy	Vulnerable, fix deferred
	20.04 LTS focal	Vulnerable, fix deferred
	18.04 LTS bionic	Vulnerable, fix deferred

Notes

john-breton

The linked PR is a specification change and does not include code changes as of 7/4/2025. May be possible to extract the fix from the 1.106.0-1 source, but unlikely.

Severity score breakdown

Parameter	Value
Base score	5.3 · Medium
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	Low
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N