CVE-2025-9731 is a vulnerability identified in the Tenda AC9 router firmware version 15.03.05.19. The issue stems from hard-coded credentials embedded within an unknown function related to the /etc_ro/shadow file, which is part of the router's administrative interface. This vulnerability allows an attacker with local access to the device to potentially authenticate using these hard-coded credentials. The attack complexity is rated as high, indicating that exploitation requires significant effort or specialized knowledge. Additionally, the exploitability is difficult, meaning that while the vulnerability exists, successfully leveraging it is not straightforward. The vulnerability does not require user interaction and does not allow remote exploitation directly, as the attack vector is local host access. The CVSS 4.0 score is low (2.0), reflecting limited impact and exploitability. The vulnerability primarily affects confidentiality due to unauthorized access possibilities but does not directly impact integrity or availability. No known exploits are currently active in the wild, and no patches have been linked yet. The presence of hard-coded credentials in a network device's administrative interface is a critical security concern because it can allow unauthorized users to gain privileged access if they can reach the device locally, such as through compromised internal networks or physical access. However, the difficulty in exploitation and requirement for local access reduce the immediate risk level.

For European organizations, the impact of this vulnerability depends on the deployment scale of Tenda AC9 routers within their network infrastructure. If these devices are used in enterprise or critical network segments, the hard-coded credentials could allow an attacker with local network access or physical access to gain administrative control over the router. This could lead to unauthorized configuration changes, interception of network traffic, or pivoting to other internal systems. However, since exploitation requires local access and is complex, the risk is somewhat mitigated in well-segmented and secured environments. Small and medium-sized enterprises or home office setups using Tenda AC9 routers might be more vulnerable, especially if network segmentation and physical security are weak. The vulnerability could also be exploited in scenarios where attackers gain initial foothold in a network and then escalate privileges by leveraging the hard-coded credentials. Given the low CVSS score and lack of known exploits, the immediate threat is limited, but the potential for privilege escalation and lateral movement within networks remains a concern.

1. Immediate mitigation should include restricting physical and local network access to Tenda AC9 devices to trusted personnel only. 2. Network segmentation should be enforced to isolate management interfaces of routers from general user networks, reducing the risk of local exploitation. 3. Monitor network traffic for unusual access patterns or attempts to authenticate using default or hard-coded credentials. 4. If possible, replace affected Tenda AC9 devices with models or firmware versions that do not contain this vulnerability. 5. Contact Tenda support or monitor official channels for firmware updates or patches addressing CVE-2025-9731 and apply them promptly once available. 6. Implement strong internal access controls and logging on network devices to detect and respond to unauthorized access attempts. 7. Conduct regular security audits and penetration testing focusing on network device configurations and access controls to identify potential exploitation paths.