CVE-2024-31208 Synapse's V2 state resolution weakness allows DoS from remote room members

2024-04-2317:26:39

CWE-770

GitHub_M

www.cve.org

cve-2024-31208

synapse

v2 state resolution

dos

remote room members

matrix homeserver

weakness

database

denial of service

server administrators

upgrade

workarounds

admin api

6.5 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

0.0004 Low

EPSS

Percentile

10.4%

JSON

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.

CNA Affected

[
  {
    "vendor": "element-hq",
    "product": "synapse",
    "versions": [
      {
        "version": "< 1.105.1",
        "status": "affected"
      }
    ]
  }
]