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osvGoogleOSV:GHSA-5CHR-WJW5-3GQ4
HistoryOct 10, 2023 - 9:27 p.m.

matrix-synapse vulnerable to denial of service due to malicious server ACL events

2023-10-1021:27:53
Google
osv.dev
6
matrix-synapse
denial of service
malicious server acl
upgrade
patch
admin api
federation

4.9 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

HIGH

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

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

5 Medium

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

49.0%

Impact

A malicious server ACL event can impact performance temporarily or permanently leading to a persistent denial of service.

Homeservers running on a closed federation (which presumably do not need to use server ACLs) are not affected.

Patches

Server administrators are advised to upgrade to Synapse 1.94.0 or later.

Workarounds

Rooms with malicious server ACL events can be purged and blocked using the admin API.

4.9 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

HIGH

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

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

5 Medium

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

49.0%