CVE-2025-27507: Zitadel Auth Bypass Vulnerability

CVE-2025-27507 Overview

CVE-2025-27507 is a critical Insecure Direct Object Reference (IDOR) vulnerability affecting Zitadel, an open-source identity infrastructure software platform. The vulnerability exists within Zitadel's Admin API, allowing authenticated users without specific IAM roles to modify sensitive settings they should not have access to. While multiple endpoints are affected, the most severe aspect of this vulnerability involves the ability to manipulate LDAP configurations, potentially compromising the entire authentication infrastructure.

Critical Impact

Authenticated users can bypass authorization controls to modify LDAP configurations and other sensitive identity management settings, potentially leading to complete authentication bypass or credential theft.

Affected Products

• Zitadel versions prior to 2.71.0
• Zitadel versions 2.70.x prior to 2.70.1
• Zitadel versions 2.69.x prior to 2.69.4
• Zitadel versions 2.68.x prior to 2.68.4
• Zitadel versions 2.67.x prior to 2.67.8
• Zitadel versions 2.66.x prior to 2.66.11
• Zitadel versions 2.65.x prior to 2.65.6
• Zitadel versions 2.64.x prior to 2.64.5
• Zitadel versions 2.63.x prior to 2.63.8

Discovery Timeline

• 2025-03-04 - CVE-2025-27507 published to NVD
• 2025-08-26 - Last updated in NVD database

Technical Details for CVE-2025-27507

Vulnerability Analysis

This vulnerability stems from improper authorization checks in Zitadel's Admin API endpoints. The IDOR vulnerability allows authenticated users to access and modify resources belonging to other users or organizations by manipulating object references in API requests. The authorization system fails to properly validate whether the requesting user has the necessary IAM-level permissions before allowing modifications to sensitive configurations.

The most critical exploitation scenario involves LDAP configuration manipulation. An attacker with basic authenticated access could potentially redirect LDAP authentication to a malicious server, enabling credential harvesting or authentication bypass. Organizations not utilizing LDAP for authentication have reduced exposure to the most severe attack scenarios, but remain vulnerable to other sensitive setting modifications.

Root Cause

The root cause is classified as CWE-639 (Authorization Bypass Through User-Controlled Key). The vulnerability exists because the Admin API endpoints use organization-level permissions (org.idp.read) instead of the appropriate IAM-level permissions (iam.idp.read) for accessing identity provider configurations. This permission misconfiguration allows users with organization-level access to view and modify IAM-level resources they should not have access to.

Attack Vector

The attack is network-based and requires the attacker to have authenticated access to the Zitadel instance. From there, the attacker can craft API requests that reference objects outside their authorization scope. The scope change capability means a successful exploit can impact resources beyond the vulnerable component, affecting the confidentiality and integrity of the entire identity infrastructure.

The following patch demonstrates the authorization fix applied to the Admin API protobuf definition:

         };
 
         option (zitadel.v1.auth_option) = {
-            permission: "org.idp.read"
+            permission: "iam.idp.read"
         };
 
         option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_operation) = {

Source: GitHub Commit Reference

This patch changes the required permission from organization-level (org.idp.read) to IAM-level (iam.idp.read), ensuring only users with appropriate administrative privileges can access these endpoints.

Detection Methods for CVE-2025-27507

Indicators of Compromise

• Unexpected modifications to LDAP or identity provider configurations in Zitadel audit logs
• API calls to Admin API endpoints from users without IAM administrative roles
• Changes to authentication settings that were not authorized through proper change management processes
• Unusual access patterns to /admin/v1/idps or similar identity provider management endpoints

Detection Strategies

• Review Zitadel audit logs for unauthorized access attempts to Admin API endpoints
• Monitor for configuration changes to LDAP settings, particularly server URLs, bind credentials, and base DNs
• Implement alerting on identity provider modifications outside of maintenance windows
• Correlate user authentication events with Admin API access to identify privilege misuse

Monitoring Recommendations

• Enable comprehensive audit logging for all Admin API operations in Zitadel
• Configure real-time alerts for any LDAP configuration changes
• Implement log analysis to detect patterns of IDOR exploitation attempts
• Regularly review user permissions to ensure principle of least privilege is maintained

How to Mitigate CVE-2025-27507

Immediate Actions Required

• Upgrade Zitadel to one of the patched versions: 2.71.0, 2.70.1, 2.69.4, 2.68.4, 2.67.8, 2.66.11, 2.65.6, 2.64.5, or 2.63.8
• Audit existing LDAP configurations for unauthorized modifications
• Review Admin API access logs for suspicious activity during the exposure window
• Verify that all identity provider settings match expected configurations

Patch Information

Zitadel has released security patches across multiple supported versions to address this vulnerability. The fix involves correcting the permission checks from organization-level to IAM-level for affected Admin API endpoints. Detailed patch information is available in the GitHub Security Advisory and the security commit.

Workarounds

• Restrict network access to the Admin API to trusted administrative networks only
• Implement additional authentication requirements (MFA) for administrative functions
• If LDAP is not required, consider disabling LDAP integration until patches can be applied
• Monitor and alert on any Admin API activity until the upgrade is complete

# Verify Zitadel version after upgrade
zitadel version

# Check current LDAP configuration for unauthorized changes
zitadel admin idp list --type ldap