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CVE-2024-37303

Synapse unauthenticated writes to the media repository allow planting of problematic content

Published: Dec 3, 2024Updated: Aug 26, 2025 Sources: CVE List NVD GHSACWE-306
NVD MITRE
5.3CVSSMEDIUM
EPSS Score
0.4%
Top 67.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-306

Affected Products

synapseelement-hq
Mixed
Communications / messaging-chat
matrix-synapsePyPIOSS Libraries
synapsematrix
On-premWeb App
Communications / messaging-chat
element-hqoss-projectCommunications
pypipackage-ecosystemOSS Libraries
matrixoss-projectGBCommunicationsaka synapse, matrix irc bridge, javascript sdk

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

2 techniques
Initial Access
View detailed technique mapping

References

https://github.com/element-hq/synapse/security/advisories/GHSA-gjgr-7834-rhxr
github.com
https://github.com/matrix-org/matrix-spec-proposals/pull/3916
github.com
https://nvd.nist.gov/vuln/detail/CVE-2024-37303
nvd.nist.gov
and 2 more references View all →

Timeline

Published
Dec 3, 2024
Last Updated
Aug 26, 2025

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