CVE-2025-11389 is a stack-based buffer overflow vulnerability identified in the Tenda AC15 router firmware version 15.03.05.18. The vulnerability resides in an unknown function related to the /goform/saveAutoQos endpoint, specifically triggered by manipulating the 'enable' argument. This manipulation causes a stack-based buffer overflow, which can be exploited remotely without requiring authentication or user interaction. The vulnerability's CVSS 4.0 score is 8.7 (high), reflecting its critical nature due to network attack vector, low complexity, no privileges required, and no user interaction needed. The impact includes potential full system compromise, allowing attackers to execute arbitrary code, disrupt device functionality, or pivot into internal networks. The exploit has been publicly released, increasing the likelihood of exploitation attempts. No official patch or firmware update has been linked yet, leaving affected devices vulnerable. The vulnerability affects only firmware version 15.03.05.18, so devices running other versions may not be impacted. The absence of known exploits in the wild suggests this is a newly disclosed vulnerability, but the public exploit availability demands urgent attention.

For European organizations, this vulnerability poses a significant risk, especially for those deploying Tenda AC15 routers in enterprise or critical infrastructure environments. Successful exploitation can lead to complete compromise of the router, enabling attackers to intercept, modify, or redirect network traffic, potentially leading to data breaches or lateral movement within corporate networks. The disruption of network availability or integrity could impact business operations, especially in sectors relying on stable internet connectivity. Given the remote exploitation capability without authentication, attackers can target exposed management interfaces over the internet or compromised internal networks. This threat is particularly concerning for small and medium enterprises (SMEs) and public institutions that may use consumer-grade routers like the Tenda AC15 without robust network segmentation or monitoring. The public availability of exploit code increases the risk of automated scanning and mass exploitation campaigns targeting vulnerable devices across Europe.

1. Immediately identify and inventory all Tenda AC15 routers running firmware version 15.03.05.18 within the organization. 2. Restrict access to router management interfaces by implementing network segmentation and firewall rules to block external access to the /goform/saveAutoQos endpoint. 3. Disable or restrict the AutoQoS feature if possible, or any related services that invoke the vulnerable function. 4. Monitor network traffic and device logs for unusual activity indicative of exploitation attempts, such as unexpected requests to /goform/saveAutoQos or anomalous command execution. 5. Apply any available firmware updates or patches from Tenda as soon as they are released; if no patch is available, consider replacing vulnerable devices with models not affected by this vulnerability. 6. Employ intrusion detection/prevention systems (IDS/IPS) with signatures targeting this exploit once available. 7. Educate IT staff about this vulnerability and the importance of securing network devices, emphasizing the risks of exposed management interfaces. 8. Consider implementing network-level anomaly detection to identify exploitation attempts targeting this vulnerability.