CVE-2025-8829 is a security vulnerability affecting multiple Linksys Wi-Fi range extender models, including RE6250, RE6300, RE6350, RE6500, RE7000, and RE9000, specifically firmware versions up to 20250801. The vulnerability resides in the function um_red within the /goform/RP_setBasicAuto endpoint. It is caused by improper sanitization of the 'hname' argument, which allows an attacker to inject arbitrary operating system commands. This flaw enables remote attackers to execute OS commands on the device without requiring user interaction or authentication, as the vulnerable endpoint can be accessed remotely. The vulnerability was publicly disclosed on August 11, 2025, and while the vendor was notified early, no response or patch has been provided to date. The CVSS v4.0 score is 5.3 (medium severity), reflecting the vulnerability's network attack vector, low attack complexity, no privileges or user interaction required, but limited impact on confidentiality, integrity, and availability. Although no known exploits have been observed in the wild, the public disclosure and availability of exploit details increase the risk of exploitation. Successful exploitation could allow attackers to gain control over the affected device, potentially leading to network reconnaissance, lateral movement, or use of the device as a foothold for further attacks within the network. Given that these devices are commonly deployed in home and small office environments, compromised devices could also be leveraged as part of botnets or to intercept or manipulate network traffic.

For European organizations, particularly small and medium enterprises (SMEs) and home office users relying on Linksys range extenders, this vulnerability poses a tangible risk. Compromise of these devices could lead to unauthorized access to internal networks, data interception, and disruption of network services. Since these devices often bridge wireless and wired networks, attackers could pivot from the compromised extender to more critical infrastructure. The lack of vendor response and patches increases the window of exposure. Additionally, given the remote exploitability without authentication, attackers can target vulnerable devices en masse, potentially impacting network availability and confidentiality. This threat is especially relevant in sectors where secure and reliable network connectivity is critical, such as finance, healthcare, and government agencies operating remotely or in distributed office environments. The vulnerability could also be exploited to create persistent backdoors or launch further attacks against connected systems, amplifying the potential damage.

Immediate mitigation steps include isolating vulnerable Linksys range extenders from critical network segments to limit lateral movement if compromised. Network administrators should monitor network traffic for unusual command execution patterns or unexpected outbound connections originating from these devices. Employ network segmentation and strict firewall rules to restrict remote access to management interfaces of these devices. Since no official patches are available, consider replacing vulnerable devices with models from vendors that provide timely security updates. If replacement is not feasible, disable remote management features and restrict access to the device's web interface to trusted internal IP addresses only. Regularly audit device firmware versions and configurations to detect unauthorized changes. Implement network intrusion detection systems (NIDS) capable of identifying command injection attempts or anomalous behavior. Finally, maintain up-to-date asset inventories to quickly identify and remediate affected devices.