EUVD-2026-10559

Comprehensive Technical Analysis of EUVD-2026-10559

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2026-10559 pertains to an authorization bypass in OneUptime, facilitated through a client-controlled is-multi-tenant-query header. This flaw can lead to cross-tenant data exposure and account takeover. The CVSS (Common Vulnerability Scoring System) base score of 10.0 indicates a critical severity level. The CVSS vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H breaks down as follows:

• Attack Vector (AV): Network (N) - The vulnerability is exploitable over the network.
• Attack Complexity (AC): Low (L) - The attack requires minimal skill or resources.
• Privileges Required (PR): Low (L) - The attacker needs low-level privileges to exploit the vulnerability.
• User Interaction (UI): None (N) - No user interaction is required for the attack to succeed.
• Scope (S): Changed (C) - The vulnerability affects resources beyond the security scope managed by the security authority.
• Confidentiality (C): High (H) - There is a high impact on the confidentiality of the data.
• Integrity (I): High (H) - There is a high impact on the integrity of the data.
• Availability (A): High (H) - There is a high impact on the availability of the system.

2. Potential Attack Vectors and Exploitation Methods

The primary attack vector involves manipulating the is-multi-tenant-query header in HTTP requests. An attacker could:

• Intercept and Modify Requests: Use tools like Burp Suite or OWASP ZAP to intercept and modify HTTP requests, setting the is-multi-tenant-query header to bypass authorization checks.
• Automated Scripts: Develop automated scripts to send crafted HTTP requests with the manipulated header, targeting specific endpoints to exfiltrate data or take over accounts.
• Phishing and Social Engineering: Trick users into executing malicious scripts or using compromised applications that exploit this vulnerability.

3. Affected Systems and Software Versions

The vulnerability affects OneUptime versions prior to 10.0.21. Organizations using these versions are at risk and should prioritize updating to the latest version.

4. Recommended Mitigation Strategies

• Immediate Patching: Upgrade to OneUptime version 10.0.21 or later, which includes the fix for this vulnerability.
• Network Segmentation: Implement network segmentation to limit the spread of potential attacks.
• Monitoring and Logging: Enhance monitoring and logging to detect unusual activity, especially around the manipulation of HTTP headers.
• Access Controls: Strengthen access controls and ensure that only authorized users have access to critical systems.
• User Education: Educate users about the risks of phishing and social engineering attacks.

5. Impact on European Cybersecurity Landscape

The vulnerability poses a significant risk to European organizations using OneUptime, particularly those handling sensitive data. Cross-tenant data exposure can lead to data breaches, financial loss, and reputational damage. The European Union's General Data Protection Regulation (GDPR) mandates stringent data protection measures, and organizations failing to address this vulnerability could face regulatory penalties.

6. Technical Details for Security Professionals

• Header Manipulation: The is-multi-tenant-query header is the key to this vulnerability. Security professionals should focus on monitoring and validating this header in all incoming requests.
• Code Review: Conduct a thorough code review to ensure that all authorization checks are properly implemented and that no other headers can be manipulated to bypass security controls.
• Intrusion Detection: Implement intrusion detection systems (IDS) and intrusion prevention systems (IPS) to detect and block attempts to manipulate the is-multi-tenant-query header.
• Regular Audits: Conduct regular security audits and vulnerability assessments to identify and mitigate similar issues proactively.

Conclusion

EUVD-2026-10559 highlights a critical vulnerability in OneUptime that requires immediate attention. Organizations should prioritize patching affected systems, enhancing monitoring and logging, and implementing robust access controls to mitigate the risk. The European cybersecurity landscape demands vigilance and proactive measures to protect against such high-severity vulnerabilities.