Description
MAS (Matrix Authentication Service) is a user management and authentication service for Matrix homeservers, written and maintained by Element. A logic flaw in matrix-authentication-service 0.20.0 through 1.4.0 allows an attacker with access to an authenticated MAS session to perform sensitive operations without entering the current password. These include changing the current password, adding or removing an e-mail address and deactivating the account. The vulnerability only affects instances which have the local password database feature enabled (passwords section in the config). Patched in matrix-authentication-service 1.4.1.
Scores
CVSS v3
8.3
EPSS
0.0009
EPSS Percentile
25.2%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-620
Status
published
Products (1)
element-hq/matrix-authentication-service
>= 0.20.0, <= 1.4.0
Published
Oct 16, 2025
Tracked Since
Feb 18, 2026