CVE-2026-1139 identifies a critical buffer overflow vulnerability in the UTT 进取 520W device firmware version 1.7.7-180627. The flaw exists in the handling of input to the /goform/ConfigExceptMSN function, which uses the unsafe strcpy function without bounds checking. This allows an attacker to send specially crafted requests remotely to overflow the buffer, potentially overwriting adjacent memory and enabling arbitrary code execution or denial of service. The vulnerability requires no user interaction and no authentication, making it highly exploitable over the network. The CVSS 4.0 score of 8.7 reflects the high impact on confidentiality, integrity, and availability, combined with ease of exploitation. Although no confirmed exploits are reported in the wild, the public disclosure of exploit code increases the risk of imminent attacks. The vendor was notified early but has not issued any patches or advisories, leaving users exposed. The vulnerability affects a specific firmware version, so devices running 1.7.7-180627 are at direct risk. The lack of vendor response and patch availability necessitates immediate mitigation efforts by users and network defenders.

For European organizations, this vulnerability poses a significant risk to network infrastructure security, particularly for those deploying UTT 进取 520W devices in critical environments. Successful exploitation could lead to full device compromise, allowing attackers to intercept, manipulate, or disrupt network traffic, potentially affecting business continuity and data confidentiality. The ability to remotely exploit without authentication increases the attack surface, especially for organizations with externally accessible management interfaces. This could facilitate lateral movement within networks or serve as a foothold for further attacks. Given the vendor's non-responsiveness, organizations cannot rely on official patches and must consider alternative protective measures. The impact is heightened in sectors with stringent data protection requirements under GDPR, where breaches could result in regulatory penalties and reputational damage.

1. Immediately restrict access to the /goform/ConfigExceptMSN endpoint by implementing network-level controls such as firewall rules or access control lists to limit exposure to trusted management networks only. 2. Deploy intrusion detection/prevention systems (IDS/IPS) with signatures or anomaly detection tuned to identify and block attempts to exploit buffer overflow patterns targeting this endpoint. 3. Conduct thorough network scans to identify devices running the vulnerable firmware version and isolate or segment them from critical infrastructure. 4. Where possible, disable remote management interfaces or move them behind VPNs or secure jump hosts to reduce direct internet exposure. 5. Implement strict input validation and filtering on any proxy or gateway devices that handle traffic to these devices to prevent malformed requests. 6. Monitor logs and network traffic for unusual activity indicative of exploitation attempts. 7. Engage with UTT or third-party security vendors for potential unofficial patches or firmware updates. 8. Plan for device replacement or firmware upgrade once a vendor patch becomes available, prioritizing critical systems. 9. Educate IT staff about this vulnerability and ensure incident response plans include scenarios involving device compromise via this flaw.