CVE-2025-12596 identifies a buffer overflow vulnerability in the Tenda AC23 router firmware version 16.03.07.52. The flaw exists in the saveParentControlInfo function within the /goform/saveParentControlInfo endpoint, where the Time argument is improperly validated or sanitized, leading to a buffer overflow condition. This vulnerability can be exploited remotely without requiring authentication or user interaction, making it highly accessible to attackers. The buffer overflow could allow attackers to execute arbitrary code on the device, potentially gaining full control over the router, or cause a denial of service by crashing the device. The vulnerability has a CVSS 4.0 base score of 8.7, reflecting its high impact and ease of exploitation. Although no confirmed exploits are currently active in the wild, the public disclosure of exploit details increases the likelihood of exploitation attempts. The Tenda AC23 is commonly used in small office and home office environments, where compromised routers can serve as entry points for lateral movement into corporate networks or be leveraged for broader attacks such as botnets or data interception. The vulnerability affects only firmware version 16.03.07.52, so devices running other versions may not be vulnerable. However, due to the critical nature of the flaw, affected users should prioritize patching or apply network-level mitigations immediately.

For European organizations, this vulnerability poses significant risks to network security and operational continuity. Exploitation could lead to unauthorized remote control of routers, enabling attackers to intercept, modify, or disrupt network traffic, compromising confidentiality and integrity of sensitive data. The potential for denial of service could disrupt business operations, especially for organizations relying on Tenda AC23 routers for internet connectivity or internal network segmentation. Small and medium enterprises (SMEs) and remote workers using these routers are particularly vulnerable, as these devices often lack advanced security monitoring. The compromise of routers can also facilitate further attacks within corporate networks, including lateral movement and data exfiltration. Given the public disclosure of exploit details, the threat landscape is likely to evolve rapidly, increasing the urgency for European entities to respond. The impact is exacerbated in sectors with high dependency on network availability and security, such as finance, healthcare, and critical infrastructure.

1. Immediate action should be taken to update the Tenda AC23 firmware to a version that patches CVE-2025-12596 once released by the vendor. 2. In the absence of an official patch, restrict external access to the /goform/saveParentControlInfo endpoint by implementing firewall rules or access control lists (ACLs) to block unauthorized traffic. 3. Employ network segmentation to isolate vulnerable routers from critical internal systems, limiting potential lateral movement. 4. Monitor network traffic for unusual patterns or attempts to access the vulnerable endpoint, using intrusion detection/prevention systems (IDS/IPS) with updated signatures. 5. Disable remote management features on the router if not required, reducing the attack surface. 6. Conduct regular audits of router firmware versions across the organization to identify and remediate vulnerable devices. 7. Educate IT staff and users about the risks associated with outdated router firmware and the importance of timely updates. 8. Consider deploying endpoint detection solutions capable of identifying anomalous router behavior indicative of compromise.