EUVD-2026-9896

Comprehensive Technical Analysis of EUVD-2026-9896

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2026-9896 affects OpenClaw versions prior to 2026.2.1, specifically when the voice-call extension is installed and enabled. The issue lies in the inbound allowlist policy validation, which incorrectly accepts empty caller IDs and uses suffix-based matching instead of strict equality. This flaw allows remote attackers to bypass inbound access controls by placing calls with missing caller IDs or numbers ending with allowlisted digits.

Severity Evaluation:

• Base Score: 9.2
• Base Score Version: 4.0
• Base Score Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N

The high base score of 9.2 indicates a critical vulnerability. The CVSS vector highlights that the attack vector is network-based (AV:N), the attack complexity is low (AC:L), and the attack requires physical interaction (AT:P). The vulnerability has high confidentiality and integrity impacts (VC:H, VI:H) but low availability impact (VA:L).

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

1. Empty Caller IDs: Attackers can place calls with missing or empty caller IDs, which are accepted by the vulnerable system.
2. Suffix-Based Matching: Attackers can exploit the suffix-based matching by using numbers that end with allowlisted digits, effectively bypassing the inbound access controls.

Exploitation Methods:

• Remote Exploitation: Attackers can remotely exploit this vulnerability by placing calls with crafted caller IDs.
• Automated Attacks: Scripts or bots can be used to automate the process of placing calls with the required conditions, increasing the scale and impact of the attack.

3. Affected Systems and Software Versions

Affected Systems:

• OpenClaw versions prior to 2026.2.1 with the voice-call extension installed and enabled.

Software Versions:

• All versions of OpenClaw from 0 to 2026.2.1.

4. Recommended Mitigation Strategies

Immediate Mitigation:

1. Upgrade Software: Upgrade to OpenClaw version 2026.2.1 or later, which includes the fix for this vulnerability.
2. Disable Voice-Call Extension: If upgrading is not immediately possible, disable the voice-call extension to mitigate the risk.
3. Implement Strict Caller ID Validation: Ensure that caller ID validation is strictly enforced and does not accept empty or suffix-based matches.

Long-Term Mitigation:

1. Regular Security Audits: Conduct regular security audits and vulnerability assessments to identify and address similar issues.
2. Network Segmentation: Implement network segmentation to limit the impact of potential attacks.
3. Intrusion Detection Systems (IDS): Deploy IDS to monitor and detect suspicious activities related to voice-call extensions.

5. Impact on European Cybersecurity Landscape

The vulnerability in OpenClaw, a widely used software in Europe, poses a significant risk to organizations relying on its voice-call extension. The potential for remote exploitation and the high impact on confidentiality and integrity make it a critical concern. Organizations across various sectors, including healthcare, finance, and government, could be affected, leading to potential data breaches, unauthorized access, and service disruptions.

6. Technical Details for Security Professionals

Vulnerability Details:

• CVE ID: CVE-2026-28446
• Assigner: VulnCheck
• References:
  • GitHub Advisory
  • GitHub Commit
  • VulnCheck Advisory

Technical Recommendations:

1. Patch Management: Ensure that all instances of OpenClaw are patched to version 2026.2.1 or later.
2. Configuration Review: Review and update the configuration of the voice-call extension to enforce strict caller ID validation.
3. Monitoring and Logging: Implement robust monitoring and logging mechanisms to detect and respond to any suspicious activities related to voice-call extensions.
4. Incident Response Plan: Develop and maintain an incident response plan specific to voice-call extension vulnerabilities to ensure quick and effective response in case of an attack.

By addressing this vulnerability promptly and implementing the recommended mitigation strategies, organizations can significantly reduce the risk of exploitation and protect their systems and data from potential attacks.