CVE-2025-20654 is a critical security vulnerability classified under CWE-787 (Out-of-bounds Write) affecting several MediaTek wireless chipset models, including MT6890, MT7622, MT7915, MT7916, MT7981, and MT7986. The root cause is an incorrect bounds check in the wlan service component, which leads to an out-of-bounds write condition. This flaw can be exploited remotely without requiring any authentication or user interaction, enabling attackers to execute arbitrary code on the affected device. The vulnerability impacts multiple SDK versions (7.4.0.1 and earlier for MT7622 and MT7915; 7.6.7.0 and earlier for MT7916, MT7981, and MT7986) and OpenWrt versions 19.07 and 21.02 for MT6890. The CVSS v3.1 score of 9.8 reflects the high severity, with attack vector being network-based, low attack complexity, no privileges required, and no user interaction needed. Successful exploitation compromises confidentiality, integrity, and availability of the device, potentially allowing full system takeover. While no exploits have been observed in the wild yet, the vulnerability's characteristics make it a prime target for attackers. MediaTek has assigned Patch ID WCNCR00406897 and Issue ID MSV-2875 to address this issue, though patch links are not yet publicly available.

The impact of CVE-2025-20654 is severe for organizations worldwide that deploy affected MediaTek chipsets in their wireless infrastructure, including routers, access points, and IoT devices. Exploitation can lead to remote code execution, allowing attackers to gain full control over the device, potentially leading to network compromise, data exfiltration, lateral movement, and disruption of services. Since no authentication or user interaction is required, attackers can launch automated attacks at scale, increasing the risk of widespread exploitation. Critical infrastructure, enterprises, and service providers relying on these chipsets may face significant operational and security risks. The vulnerability undermines the confidentiality, integrity, and availability of network communications and devices, potentially enabling persistent threats and advanced attacks. The lack of known exploits in the wild currently provides a window for proactive mitigation, but the high severity demands urgent attention.

Organizations should immediately inventory devices using the affected MediaTek chipsets and verify their SDK or firmware versions. They must prioritize applying patches from MediaTek as soon as they become available (Patch ID WCNCR00406897). Until patches are deployed, network segmentation should be enforced to isolate vulnerable devices from critical assets. Employ strict network monitoring and intrusion detection systems to identify anomalous wlan traffic indicative of exploitation attempts. Disable or restrict remote management interfaces on affected devices to reduce exposure. Vendors and integrators should accelerate firmware updates and communicate risks to end users. Additionally, organizations should consider deploying network-level protections such as firewall rules to limit access to vulnerable devices and conduct regular vulnerability scanning to detect unpatched systems. Coordinated vulnerability disclosure and sharing of indicators of compromise will aid in early detection of exploitation attempts.