Synapse is an open-source Matrix homeserver. Synapse versions before 1.106 are vulnerable to a disk fill attack, where an unauthenticated adversary can induce Synapse to download and cache large amounts of remote media. The default rate limit strategy is insufficient to mitigate this. This can lead to a denial of service, ranging from further media uploads/downloads failing to completely unavailability of the Synapse process, depending on how Synapse was deployed. Synapse 1.106 introduces a new "leaky bucket" rate limit on remote media downloads to reduce the amount of data a user can request at a time. This does not fully address the issue, but does limit an unauthenticated user's ability to request large amounts of data to be cached.
History

Tue, 03 Dec 2024 19:15:00 +0000

Type Values Removed Values Added
First Time appeared Element-hq
Element-hq synapse
CPEs cpe:2.3:a:element-hq:synapse:*:*:*:*:*:*:*:*
Vendors & Products Element-hq
Element-hq synapse
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 03 Dec 2024 17:15:00 +0000

Type Values Removed Values Added
Description Synapse is an open-source Matrix homeserver. Synapse versions before 1.106 are vulnerable to a disk fill attack, where an unauthenticated adversary can induce Synapse to download and cache large amounts of remote media. The default rate limit strategy is insufficient to mitigate this. This can lead to a denial of service, ranging from further media uploads/downloads failing to completely unavailability of the Synapse process, depending on how Synapse was deployed. Synapse 1.106 introduces a new "leaky bucket" rate limit on remote media downloads to reduce the amount of data a user can request at a time. This does not fully address the issue, but does limit an unauthenticated user's ability to request large amounts of data to be cached.
Title Synapse denial of service through media disk space consumption
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2024-12-03T17:04:15.839Z

Updated: 2024-12-03T18:56:17.082Z

Reserved: 2024-06-05T20:10:46.497Z

Link: CVE-2024-37302

cve-icon Vulnrichment

Updated: 2024-12-03T18:55:52.653Z

cve-icon NVD

Status : Received

Published: 2024-12-03T17:15:10.733

Modified: 2024-12-03T17:15:10.733

Link: CVE-2024-37302

cve-icon Redhat

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