CVE-2020-1697 in KeyCloak
Summary
by MITRE
It was found in all keycloak versions before 9.0.0 that links to external applications (Application Links) in the admin console are not validated properly and could allow Stored XSS attacks. An authed malicious user could create URLs to trick users in other realms, and possibly conduct further attacks.
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Analysis
by VulDB Data Team • 05/11/2025
The vulnerability identified as CVE-2020-1697 represents a critical stored cross-site scripting flaw within the Keycloak identity and access management platform. This vulnerability affects all Keycloak versions prior to 9.0.0 and specifically targets the admin console's handling of external application links. The flaw resides in the improper validation of URL inputs when administrators configure application links within the Keycloak console interface. When malicious users with authentication credentials create application links containing malicious script code, this code gets stored in the system and subsequently executed whenever other authenticated users view the admin console. The vulnerability is classified under CWE-79 as a failure to sanitize user input, specifically in the context of web application security where user-supplied data is not properly validated or escaped before being rendered to other users.
The operational impact of CVE-2020-1697 extends beyond simple XSS execution as it creates a persistent threat vector within Keycloak environments. An authenticated malicious user can craft malicious URLs that appear legitimate within the Keycloak admin console, potentially tricking other administrators or users into executing malicious scripts. This stored XSS vulnerability enables attackers to perform actions such as stealing session cookies, redirecting users to malicious sites, or executing arbitrary JavaScript code in the context of other users' browsers. The attack vector is particularly dangerous because it leverages the trust relationship between Keycloak administrators and the system interface, allowing an attacker to compromise multiple realms where the vulnerable Keycloak instance is deployed. The vulnerability aligns with ATT&CK technique T1566.001 for credential access through phishing and T1059.007 for command and scripting interpreter via script-based attacks.
The security implications of this vulnerability are significant for organizations relying on Keycloak for identity management and access control. Organizations with multiple realms using vulnerable Keycloak versions face potential compromise of their entire authentication infrastructure, as the malicious scripts could be used to escalate privileges or extract sensitive authentication tokens. The vulnerability demonstrates a failure in input validation and output encoding practices that should be implemented at multiple layers within web applications. Security teams must consider the broader impact on their identity infrastructure, as compromised Keycloak instances could lead to unauthorized access to protected resources across all connected applications. The vulnerability also highlights the importance of regular security updates and patch management processes within identity and access management systems, particularly those handling authentication tokens and user session information. Organizations should immediately implement mitigation strategies including immediate patching to version 9.0.0 or later, implementing additional input validation measures, and monitoring for suspicious activity in the Keycloak admin console. The vulnerability serves as a reminder of the critical importance of validating all user-supplied inputs and ensuring proper output encoding in web applications, particularly within administrative interfaces that handle sensitive configuration data.
This vulnerability exemplifies the broader category of insecure data handling within identity management systems, where the combination of user authentication and administrative interfaces creates unique attack surfaces. The flaw demonstrates how seemingly benign configuration features can become dangerous when proper security controls are not implemented, emphasizing the need for comprehensive security testing of administrative interfaces. Organizations should implement additional security controls such as content security policies and regular security assessments of their identity management infrastructure to prevent similar vulnerabilities from being exploited. The vulnerability also underscores the importance of maintaining current security practices and staying informed about security advisories for identity and access management platforms that are critical to organizational security infrastructure.