CVE-2025-13806 identifies an improper authorization vulnerability in the NutzBoot framework, specifically affecting the Transaction API component within the EthModule.java file of the nutzboot-demo-simple-web3j module. The vulnerability is caused by insufficient validation or authorization checks on the manipulation of the 'from', 'to', and 'wei' parameters, which represent transaction details in blockchain-related operations. This flaw allows remote attackers to craft malicious requests that bypass authorization controls, potentially enabling unauthorized transaction operations. The vulnerability requires no authentication or user interaction, making it remotely exploitable over the network. The CVSS 4.0 base score of 6.9 reflects a medium severity, considering the ease of exploitation and the limited but non-negligible impact on confidentiality, integrity, and availability. While no exploits have been observed in the wild, the public disclosure increases the risk of exploitation attempts. The affected version is 2.6.0-SNAPSHOT, indicating that development or pre-release versions are impacted. The lack of available patches at the time of disclosure necessitates immediate mitigation efforts by users of NutzBoot in sensitive environments.

For European organizations, the vulnerability poses a risk primarily to applications leveraging NutzBoot for blockchain transaction processing or similar functionalities. Unauthorized manipulation of transaction parameters could lead to fraudulent transactions, data tampering, or denial of service conditions affecting business operations. This can undermine trust in blockchain-based services, cause financial losses, and potentially expose sensitive transaction data. Organizations in finance, supply chain, and public sectors using NutzBoot may face reputational damage and regulatory scrutiny under GDPR if personal or transactional data confidentiality is compromised. The medium severity suggests that while the impact is not catastrophic, it is significant enough to warrant prompt attention to avoid exploitation. The remote and unauthenticated nature of the vulnerability increases the attack surface, especially for internet-facing services.

1. Monitor the vendor's official channels for patches or updates addressing CVE-2025-13806 and apply them promptly once available. 2. Implement strict input validation and sanitization on all transaction-related parameters ('from', 'to', 'wei') to prevent unauthorized manipulation. 3. Employ network-level controls such as firewalls and API gateways to restrict access to the Transaction API endpoints only to trusted sources. 4. Enable detailed logging and continuous monitoring of transaction API usage to detect anomalous or unauthorized requests early. 5. Consider deploying Web Application Firewalls (WAFs) with custom rules targeting suspicious parameter manipulations. 6. Conduct internal code reviews and security assessments of custom modules interacting with NutzBoot to identify similar authorization weaknesses. 7. Educate developers and system administrators about the risks of improper authorization and secure coding practices related to blockchain transaction handling.