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
AI Score
Confidence
High
SSVC
Exploitation
none
Automatable
no
Technical Impact
partial
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.
[
{
"vendor": "element-hq",
"product": "synapse",
"versions": [
{
"status": "affected",
"version": "< 1.105.1"
}
]
}
]
github.com/element-hq/synapse/commit/55b0aa847a61774b6a3acdc4b177a20dc019f01a
github.com/element-hq/synapse/releases/tag/v1.105.1
github.com/element-hq/synapse/security/advisories/GHSA-3h7q-rfh9-xm4v
lists.fedoraproject.org/archives/list/[email protected]/message/R6FCCO4ODTZ3FDS7TMW76PKOSEL2TQVB/
lists.fedoraproject.org/archives/list/[email protected]/message/RR53FNHV446CB37TP45GZ6F6HZLZCK3K/
lists.fedoraproject.org/archives/list/[email protected]/message/VSF4NJJSTSQRJQ47PLYYSCFYKJBP7DET/
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
AI Score
Confidence
High
SSVC
Exploitation
none
Automatable
no
Technical Impact
partial