CVE-2024-31208

MEDIUM EPSS 70.3%
Published Apr 23, 20242y ago · Modified Jun 17, 20262w ago
6.5 CVSS 3.1
Medium
Find Similar
Published Apr 23, 2024 2y ago
Last Modified Jun 17, 2026 2w ago

Description

Synapse is an open-source Matrix homeserver. A remote Matrix user with malicious intent, sharing a room with Synapse instances before 1.105.1, can dispatch specially crafted events to exploit a weakness in the V2 state resolution algorithm. This can induce high CPU consumption and accumulate excessive data in the database of such instances, resulting in a denial of service. Servers in private federations, or those that do not federate, are not affected. Server administrators should upgrade to 1.105.1 or later. Some workarounds are available. One can ban the malicious users or ACL block servers from the rooms and/or leave the room and purge the room using the admin API.

CVSS Details

Base Score
6.5
Exploitability
2.8
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
70.3% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-770

Affected Products 4

VendorProductVersionRange
matrixsynapse* <1.105.1
fedoraprojectfedora38any
fedoraprojectfedora39any
fedoraprojectfedora40any

References 6

  • github.com https://github.com/element-hq/synapse/commit/55b0aa847a61774b6a3acdc4b177a20dc019f01a
    Patch
  • github.com https://github.com/element-hq/synapse/releases/tag/v1.105.1
    Release Notes
  • github.com https://github.com/element-hq/synapse/security/advisories/GHSA-3h7q-rfh9-xm4v
    Vendor Advisory
  • lists.fedoraproject.org https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/R6FCCO4ODTZ3FDS7TMW76PKOSEL2TQVB/
    Mailing ListThird Party Advisory
  • lists.fedoraproject.org https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RR53FNHV446CB37TP45GZ6F6HZLZCK3K/
    Mailing ListThird Party Advisory
  • lists.fedoraproject.org https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VSF4NJJSTSQRJQ47PLYYSCFYKJBP7DET/
    Mailing ListThird Party Advisory

Remediation

  • github.com https://github.com/element-hq/synapse/commit/55b0aa847a61774b6a3acdc4b177a20dc019f01a
    Patch