CVE-2023-49867 is a high-severity stack-based buffer overflow vulnerability identified in the boa web server component's formWsc functionality within the Realtek rtl819x Jungle SDK version 3.4.11. This SDK is embedded in the LevelOne WBR-6013 wireless router, specifically in firmware version RER4_A_v3411b_2T2R_LEV_09_170623. The vulnerability arises due to improper bounds checking when processing HTTP requests, allowing an attacker to send a crafted sequence of HTTP requests that overflow a stack buffer. This overflow can overwrite the stack, enabling remote code execution (RCE) on the device without requiring user interaction. The CVSS 3.1 vector (AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H) indicates that exploitation requires network access and high privileges, but no user interaction is needed. Successful exploitation compromises confidentiality, integrity, and availability of the device, potentially allowing attackers to control the router, intercept or manipulate traffic, or disrupt network services. No patches or firmware updates have been publicly released yet, and no known exploits are currently observed in the wild. The vulnerability is tracked under CWE-121 (stack-based buffer overflow), a common and dangerous class of memory corruption bugs. The affected product is primarily used in small office/home office environments but may also be deployed in enterprise branch offices.

For European organizations, exploitation of this vulnerability could lead to full compromise of affected LevelOne WBR-6013 routers, resulting in unauthorized access to internal networks, interception or manipulation of sensitive data, and disruption of network availability. This is particularly critical for organizations relying on these routers for perimeter security or VPN termination. Confidentiality breaches could expose personal data protected under GDPR, leading to regulatory penalties. Integrity and availability impacts could disrupt business operations, especially in sectors like finance, healthcare, and critical infrastructure. The requirement for high privileges to exploit may limit risk to some extent, but insider threats or compromised internal hosts could leverage this vulnerability. The lack of available patches increases exposure duration. Additionally, attackers could use compromised routers as footholds for lateral movement or launching further attacks within European networks.

Immediate mitigation involves network segmentation to isolate vulnerable devices from untrusted networks and restrict access to the router's management interface. Deploy network-level filtering to block suspicious or malformed HTTP requests targeting the device, particularly those exploiting the formWsc functionality. Monitor network traffic for anomalies indicating exploitation attempts. Since no official patches are currently available, organizations should contact LevelOne support for firmware updates or advisories. Consider replacing affected devices with models not using the vulnerable SDK. Implement strict access controls and multi-factor authentication for device management to reduce the risk of privilege escalation. Regularly audit device firmware versions and configurations to ensure compliance. Employ intrusion detection/prevention systems (IDS/IPS) with signatures for this vulnerability once available. Maintain comprehensive logging and incident response plans to quickly detect and respond to exploitation attempts.