CVE-2026-88770
Description
A flaw was found in the Device Authorization Grant flow of Keycloak, an identity and access management solution. The issue occurs because the token redemption process fails to check if a user account is currently locked due to brute-force protection. If an attacker has an active session for a locked account, they can complete the device login process and receive new security tokens. This allows the attacker to maintain access to the account even when it should be temporarily disabled to prevent unauthorized entry.
Statement
The Red Hat Product Security team has assessed the severity of this vulnerability as Moderate, given that exploitation requires the attacker to hold a valid SSO browser session for the target account established prior to the lockout. Successful exploitation allows an attacker to bypass brute-force protection policies and obtain valid tokens for a locked account. The vulnerability's root cause is the missing brute-force status check in the Device Authorization Grant token redemption code path.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | N/A | 6.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism
An attacker could perform an arbitrary number of authentication attempts using different passwords, and eventually gain access to the targeted account using a brute force attack.
Acknowledgements
Red Hat would like to thank Sunil Tripathy for reporting this issue.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
