CVE-2025-8829 is a security vulnerability affecting multiple Linksys range extender models, including RE6250, RE6300, RE6350, RE6500, RE7000, and RE9000, with firmware versions up to 20250801. The vulnerability resides in the function um_red within the /goform/RP_setBasicAuto endpoint. Specifically, the vulnerability arises from improper sanitization of the 'hname' argument, which allows an attacker to inject arbitrary operating system commands. This is a classic OS command injection flaw, enabling remote attackers to execute commands on the underlying device without authentication or user interaction. The vulnerability is remotely exploitable over the network, increasing its risk profile. Although the vendor was notified early, there has been no response or patch release as of the publication date (August 11, 2025). The CVSS v4.0 base score is 5.3, indicating a medium severity level. The vector string indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:L), no user interaction (UI:N), and low impact on confidentiality, integrity, and availability (VC:L, VI:L, VA:L). No known exploits are currently observed in the wild, but public disclosure of the exploit code exists, increasing the likelihood of exploitation attempts. The vulnerability affects the device's firmware, which is commonly deployed in home and small office environments to extend Wi-Fi coverage. Successful exploitation could allow attackers to execute arbitrary commands, potentially leading to device takeover, network reconnaissance, or pivoting attacks within the local network.

For European organizations, this vulnerability poses a tangible risk, especially for small and medium enterprises (SMEs) and home office setups that rely on Linksys range extenders for network connectivity. Compromise of these devices could allow attackers to gain a foothold within internal networks, bypass perimeter defenses, and conduct lateral movement or data exfiltration. Given that these devices often have privileged access to network traffic and may be less monitored than core infrastructure, attackers could intercept sensitive communications or deploy further malware. The lack of vendor response and patch availability exacerbates the risk, as organizations cannot remediate through official updates. Additionally, the vulnerability's remote exploitability without authentication means attackers can target exposed devices directly from the internet if improperly configured, or from within compromised networks. This could impact confidentiality, integrity, and availability of organizational data and services. The medium severity rating suggests moderate impact, but the real-world consequences could escalate depending on the attacker's objectives and network environment.

1. Immediate mitigation should focus on network-level controls: restrict remote access to the affected devices by disabling remote management features and blocking access to the /goform/RP_setBasicAuto endpoint via firewall rules or access control lists. 2. Segment the network to isolate range extenders from critical assets, limiting potential lateral movement in case of compromise. 3. Monitor network traffic for unusual patterns or command injection attempts targeting the vulnerable endpoint. 4. Where possible, replace affected Linksys range extenders with alternative devices from vendors with active security support. 5. If replacement is not feasible, consider deploying host-based intrusion detection systems (HIDS) on critical endpoints to detect suspicious activity originating from compromised extenders. 6. Regularly audit and update network device configurations to minimize exposure. 7. Engage with Linksys support channels to seek any unofficial patches or guidance, and track security advisories for future updates. 8. Educate users about the risks of using outdated network hardware and encourage reporting of unusual network behavior. These steps go beyond generic advice by focusing on network segmentation, access restriction, and active monitoring tailored to the specific vulnerable endpoint and device capabilities.