// For flags

CVE-2021-32659

Automatic room upgrade handling can be used maliciously to bridge a room non-consentually

Severity Score

4.9
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

Matrix-appservice-bridge is the bridging service for the Matrix communication program's application services. In versions 2.6.0 and earlier, if a bridge has room upgrade handling turned on in the configuration (the `roomUpgradeOpts` key when instantiating a new `Bridge` instance.), any `m.room.tombstone` event it encounters will be used to unbridge the current room and bridge into the target room. However, the target room `m.room.create` event is not checked to verify if the `predecessor` field contains the previous room. This means that any malicious admin of a bridged room can repoint the traffic to a different room without the new room being aware. Versions 2.6.1 and greater are patched. As a workaround, disabling the automatic room upgrade handling can be done by removing the `roomUpgradeOpts` key from the `Bridge` class options.

Matrix-appservice-bridge es el servicio de bridge para los servicios de aplicación del programa de comunicación Matrix. En versiones 2.6.0 y anteriores, si un bridge presenta activada la administración de actualización de salas en la configuración (la clave "roomUpgradeOpts" al instanciar una nueva instancia de "Bridge"), cualquier evento "m.room.tombstone" que encuentre será usada para deshacer el bridge de la sala actual y pasar a la sala de destino. Sin embargo, el evento "m.room.create" de la sala de destino no es comprobado para verificar si el campo "predecessor" contiene la sala anterior. Esto significa que cualquier administrador malicioso de una sala bridged puede redirigir el tráfico a una sala diferente sin que la nueva sala lo sepa. Las versiones 2.6.1 y superiores están parcheadas. Como solución, deshabilitando el manejo de la actualización automática de salas eliminando la clave "roomUpgradeOpts" de las opciones de la clase "Bridge"

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Network
Attack Complexity
Medium
Authentication
Single
Confidentiality
None
Integrity
Partial
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-05-12 CVE Reserved
  • 2021-06-16 CVE Published
  • 2023-03-07 EPSS Updated
  • 2024-08-03 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-306: Missing Authentication for Critical Function
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Matrix
Search vendor "Matrix"
 Matrix-appservice-bridge
Search vendor "Matrix" for product "Matrix-appservice-bridge"
 < 2.6.1
Search vendor "Matrix" for product "Matrix-appservice-bridge" and version " < 2.6.1"
node.js
Affected