CVE-2026-97175
Description
A flaw was found in the idp-auto-link authenticator of the keycloak-services component, which handles user identity federation. The issue occurs when Keycloak automatically links an incoming identity from an external provider to an existing local account based on an email address without verifying if the provider has validated that email. This can allow an attacker to take over a victim's account by using a matching unverified email address at a brokered provider.
Statement
The Red Hat Product Security team has assessed the severity of this vulnerability as Important, given that an attacker must possess an account at a brokered identity provider. Successful exploitation allows an attacker to perform a full account takeover, including changing the victim's email and password. The vulnerability's root cause is the failure to verify the email verified claim before automatically linking and authenticating a federated identity to an existing local account.
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.
--- CME Mitigation Guidance (2026-11-06) ---
Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.
The highest-value action is to require verification of the email verified claim before linking brokered identities to local accounts in the idp-auto-link authenticator: upgrade to Red Hat build of Keycloak 26.4.17 (or the fixed Rhbk/Keycloak Rhel/Keycloak Services builds), which verify the email verified claim before automatically linking an incoming brokered identity to an existing local account, closing federated identity login using unverified matching email address. Until patched, this is a concern on Keycloak deployments configured with the idp-auto-link authenticator in the first-broker-login flow, so audit brokered external identity providers to ensure they enforce email verification, or avoid using external providers that permit arbitrary unverified email addresses matching existing local accounts. As a compensating measure, Enforce multi-factor authentication on target Keycloak accounts to prevent attackers from completing account takeovers even if the federated identity is automatically linked. These controls limit blast radius and contain exploitation, but they do not fix the underlying improper authentication defect — apply the upstream patch to fully remediate.
Highest-impact CME: CME-801 Multi-Factor Authentication (MFA) (medium)
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.8 | N/A | 8.8 |
| 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 | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability,Access Control
Technical Impact: Read Application Data; Gain Privileges or Assume Identity; Execute Unauthorized Code or Commands
This weakness can lead to the exposure of resources or functionality to unintended actors, possibly providing attackers with sensitive information or even execute arbitrary code.
Acknowledgements
Red Hat would like to thank ProofSpear Security Labs (research@proofspear.io) for reporting this issue.
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