CVE-2025-11387 is a stack-based buffer overflow vulnerability identified in the Tenda AC15 router firmware version 15.03.05.18. The vulnerability resides in an unspecified function handling the /goform/fast_setting_pppoe_set endpoint, specifically in the processing of the Password parameter. Due to insufficient bounds checking, an attacker can supply a crafted Password argument that overflows the stack buffer, potentially overwriting the return address or other control data. This flaw can be exploited remotely over the network without requiring authentication or user interaction, making it highly accessible to attackers. Successful exploitation can lead to arbitrary code execution on the device, allowing attackers to gain control over the router. This could enable interception or manipulation of network traffic, disruption of network services, or use of the device as a foothold for further attacks within the network. The vulnerability has a CVSS 4.0 base score of 8.7, reflecting its high impact and ease of exploitation. While no known exploits are currently reported in the wild, the public disclosure increases the likelihood of exploitation attempts. The lack of available patches at the time of disclosure necessitates immediate mitigation efforts by affected users and organizations.

The impact of CVE-2025-11387 is significant for organizations using Tenda AC15 routers with the vulnerable firmware. Exploitation can lead to full compromise of the router, allowing attackers to execute arbitrary code remotely. This compromises the confidentiality, integrity, and availability of network communications passing through the device. Attackers could intercept sensitive data, redirect traffic, launch man-in-the-middle attacks, or disrupt network connectivity. In enterprise or critical infrastructure environments, this could result in operational downtime, data breaches, and loss of trust. Additionally, compromised routers can be leveraged as entry points for lateral movement within internal networks, increasing the risk of broader organizational compromise. The ease of remote exploitation without authentication or user interaction amplifies the threat, making widespread attacks feasible if the vulnerability is not addressed promptly.

1. Immediate firmware update: Monitor Tenda's official channels for a security patch addressing CVE-2025-11387 and apply it as soon as it becomes available. 2. Network segmentation: Isolate vulnerable Tenda AC15 devices from critical network segments to limit potential attacker movement. 3. Access control: Restrict remote management access to the router, ideally limiting it to trusted IP addresses or disabling remote management entirely. 4. Intrusion detection: Deploy network-based intrusion detection systems (NIDS) to monitor for suspicious traffic targeting the /goform/fast_setting_pppoe_set endpoint or unusual POST requests containing anomalous Password parameters. 5. Temporary firewall rules: Block or filter incoming traffic to the router's management interface from untrusted networks until patches are applied. 6. Device replacement: For environments where patching is delayed or unsupported, consider replacing vulnerable devices with models from vendors with robust security update practices. 7. Regular auditing: Conduct periodic security assessments of network devices to detect unauthorized changes or signs of compromise. These measures collectively reduce the attack surface and mitigate the risk until a permanent fix is deployed.