CVE-2025-66028: Oneuptime Privilege Escalation Flaw

CVE-2025-66028 Overview

OneUptime is an open-source solution for monitoring and managing online services. A privilege escalation vulnerability exists in versions prior to 8.0.5567 that allows attackers to manipulate the login response to gain unauthorized access to the admin dashboard interface. The vulnerability stems from improper access control during the authentication process, where the server response includes a client-side trust parameter called isMasterAdmin that can be intercepted and modified.

Critical Impact

Attackers can bypass normal authorization controls by intercepting and modifying the isMasterAdmin parameter from false to true during login, potentially gaining access to administrative interfaces. However, backend permission checks may still restrict actual data access and interactions.

Affected Products

• Hackerbay OneUptime versions prior to 8.0.5567

Discovery Timeline

• 2025-11-26 - CVE CVE-2025-66028 published to NVD
• 2025-12-05 - Last updated in NVD database

Technical Details for CVE-2025-66028

Vulnerability Analysis

This vulnerability represents a classic authorization bypass through client-side trust. The OneUptime authentication system improperly relies on a client-controllable parameter (isMasterAdmin) in the login response to determine administrative access to the dashboard interface. While the application does appear to implement some server-side permission checks that may prevent full data access, the architectural flaw allows unauthorized users to access and view the administrative interface itself.

The vulnerability is categorized under CWE-284 (Improper Access Control), which encompasses issues where software fails to properly restrict access to functionality or data. In this case, the trust boundary is incorrectly placed on the client side, allowing response manipulation to bypass initial authorization checks.

Root Cause

The root cause lies in the authentication flow design where administrative role determination is partially delegated to the client side. The isMasterAdmin boolean parameter included in the login response is trusted by the frontend application to render the appropriate user interface. This design pattern violates the principle of server-side authorization enforcement, where all access control decisions should be made and enforced exclusively on the server.

Attack Vector

The attack exploits the network-based authentication flow and requires no special privileges or user interaction:

1. An attacker initiates a standard login request to the OneUptime application
2. Using a proxy tool (such as Burp Suite or OWASP ZAP), the attacker intercepts the server's login response
3. The attacker locates the isMasterAdmin parameter in the JSON response body
4. The parameter value is modified from false to true
5. The modified response is forwarded to the client application
6. The frontend application trusts the manipulated response and renders the admin dashboard interface

While this grants visual access to administrative interfaces, the description notes that backend permission checks may still prevent actual data manipulation or viewing, limiting the practical impact of the vulnerability.

Detection Methods for CVE-2025-66028

Indicators of Compromise

• Unusual access patterns to admin dashboard endpoints from non-administrator user accounts
• Login response modifications detected in application or proxy logs
• Users accessing administrative paths without corresponding role assignments in the backend database
• Discrepancies between client-reported role and server-side role records

Detection Strategies

• Implement server-side logging that tracks attempts to access admin functionality and compares against authorized user lists
• Deploy web application firewalls (WAF) with rules to detect response tampering patterns
• Enable application-level audit logging for all authentication events and role-based access attempts
• Monitor for proxy-related HTTP headers that may indicate interception tools in use

Monitoring Recommendations

• Review authentication and authorization logs for anomalous access patterns
• Implement real-time alerting for unauthorized admin dashboard access attempts
• Cross-reference user session data with backend permission records to identify inconsistencies
• Monitor network traffic for signs of man-in-the-middle activity during authentication flows

How to Mitigate CVE-2025-66028

Immediate Actions Required

• Upgrade OneUptime to version 8.0.5567 or later immediately
• Review access logs to identify any potential exploitation attempts prior to patching
• Audit current user permissions and admin access to ensure no unauthorized escalation occurred
• Implement additional server-side authorization checks as a defense-in-depth measure

Patch Information

The vulnerability has been addressed in OneUptime version 8.0.5567. The fix ensures that administrative role determination is performed exclusively on the server side and is not influenced by client-modifiable response parameters. Organizations should upgrade to the patched version as soon as possible.

For additional details, refer to the GitHub Security Advisory GHSA-675q-66gf-gqg8 and the associated commit.

Workarounds

• Deploy a reverse proxy or WAF that validates response integrity before delivery to clients
• Implement strict server-side role validation for all administrative endpoint requests, independent of client-reported role information
• Enable additional authentication factors for administrative access until the patch can be applied
• Restrict network access to the OneUptime application to trusted networks only as a temporary measure