Allocation of Resources Without Limits in Keycloak

2023-12-1418:30:22

Google

osv.dev

keycloak

memory consumption

offline tokens

attack

admin ui

excessive cpu consumption

CVSS3

7.7

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

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

AI Score

7.4

Confidence

High

EPSS

0.001

Percentile

39.4%

JSON

An unconstrained memory consumption vulnerability was discovered in Keycloak. It can be triggered in environments which have millions of offline tokens (> 500,000 users with each having at least 2 saved sessions). If an attacker creates two or more user sessions and then open the “consents” tab of the admin User Interface, the UI attempts to load a huge number of offline client sessions leading to excessive memory and CPU consumption which could potentially crash the entire system.