CVE-2025-15621: Sparx Enterprise Architect Auth Bypass Flaw

CVE-2025-15621 Overview

CVE-2025-15621 is a vulnerability affecting Sparx Systems Enterprise Architect where OAuth2 credentials are insufficiently protected during the OpenID authentication process. The client application fails to properly verify the receiver of OAuth2 credentials, potentially allowing unauthorized parties to intercept authentication tokens.

Critical Impact

Attackers with local access may be able to capture OAuth2 credentials during OpenID authentication flows, potentially leading to credential theft and unauthorized access to connected services.

Affected Products

• Sparx Systems Enterprise Architect (versions prior to security fix)

Discovery Timeline

• 2026-04-16 - CVE CVE-2025-15621 published to NVD
• 2026-04-16 - Last updated in NVD database

Technical Details for CVE-2025-15621

Vulnerability Analysis

This vulnerability falls under CWE-522 (Insufficiently Protected Credentials), indicating a weakness in how the application handles sensitive authentication data. The core issue lies in the OAuth2/OpenID Connect implementation within Sparx Systems Enterprise Architect, where the client fails to validate the intended recipient of credential data during the authentication handshake.

In a properly implemented OAuth2/OpenID Connect flow, the client application should verify that credential tokens are being sent to the legitimate authorization server and that responses originate from trusted sources. When this verification is absent or improperly implemented, it creates an opportunity for credential interception.

The local attack vector with high attack complexity suggests that exploitation requires specific conditions to be met, including the attacker having local system access and user interaction. Despite these prerequisites, successful exploitation could result in high confidentiality impact, as captured credentials may provide access to other connected systems and services.

Root Cause

The root cause of this vulnerability is the insufficient verification of the OAuth2 credential receiver during OpenID authentication. The client application does not adequately validate that authentication tokens are being exchanged with the legitimate authorization endpoint, creating a trust boundary violation. This implementation oversight allows potential interception of credential data when an attacker can position themselves in the authentication flow.

Attack Vector

The attack requires local access to the system where Sparx Systems Enterprise Architect is running. An attacker would need to establish a position to intercept OAuth2 tokens during the OpenID authentication process. This could potentially be achieved through:

The attacker must first gain local access to the target system. When a legitimate user initiates an OpenID authentication flow within Enterprise Architect, the attacker could exploit the lack of receiver verification to capture the OAuth2 credentials. This may involve redirecting authentication responses or intercepting tokens in transit within the local environment. The attack complexity is high, requiring precise timing and specific local conditions to be successful.

Detection Methods for CVE-2025-15621

Indicators of Compromise

• Unusual OAuth2 token requests or authentication attempts from unexpected local processes
• Anomalous network traffic during Enterprise Architect OpenID authentication sessions
• Unexpected modifications to authentication configuration files or registry entries
• Multiple failed or suspicious authentication events in application logs

Detection Strategies

• Monitor local authentication events and OAuth2 token exchanges for anomalies
• Implement endpoint detection rules to identify unauthorized interception of authentication flows
• Review Enterprise Architect logs for unusual OpenID Connect authentication patterns
• Deploy network monitoring to detect credential data being sent to unauthorized endpoints

Monitoring Recommendations

• Enable detailed logging for OAuth2/OpenID authentication events in Enterprise Architect
• Monitor for suspicious local processes attempting to intercept authentication traffic
• Implement alerting on unusual authentication patterns or token acquisition attempts
• Review system logs for evidence of man-in-the-middle positioning on the local system

How to Mitigate CVE-2025-15621

Immediate Actions Required

• Review the Sparx Systems EA Version History for security updates addressing this vulnerability
• Apply the latest security patches from Sparx Systems as soon as available
• Restrict local access to systems running Enterprise Architect to trusted users only
• Consider temporarily disabling OpenID authentication until patches are applied

Patch Information

Refer to the Sparx Systems EA Version History for details on security updates and patch availability. Organizations should prioritize updating to the latest version of Enterprise Architect that addresses this credential protection vulnerability.

Workarounds

• Use alternative authentication methods (non-OpenID) until patches are applied
• Implement additional network segmentation to limit local attack surface
• Enable strict endpoint validation where possible through network security controls
• Monitor authentication sessions closely and terminate any suspicious activity
• Restrict user permissions on systems running Enterprise Architect to minimize exposure

# Configuration example - Audit Enterprise Architect authentication settings
# Review and monitor OpenID configuration files for unauthorized changes

# On Windows systems, monitor relevant log locations:
# Check Enterprise Architect log directory for authentication events
dir "%APPDATA%\Sparx Systems\EA\Logs"

# Enable Windows Security auditing for credential access
auditpol /set /subcategory:"Credential Validation" /success:enable /failure:enable