CVE-2025-20717 is a stack overflow vulnerability identified in the WLAN Access Point (AP) driver used in multiple MediaTek chipsets, including MT6890, MT7615, MT7622, MT7663, MT7915, MT7916, MT7981, and MT7986. The root cause is an incorrect bounds check in the driver code, which allows an out-of-bounds write to the stack memory. This type of vulnerability can corrupt the stack, potentially overwriting return addresses or other control data, leading to arbitrary code execution or system crashes. However, exploitation requires that the attacker already possesses System-level privileges on the device, limiting the initial attack vector to local or already compromised users. No user interaction is necessary, meaning the vulnerability can be triggered programmatically once the attacker has sufficient access. The affected software versions include MediaTek SDK release 7.6.7.2 and earlier, as well as openWRT versions 19.07 and 21.02 for the MT6890 chipset. The vulnerability is categorized under CWE-121, which corresponds to stack-based buffer overflows, a well-known class of memory corruption bugs. Although no public exploits have been reported yet, the vulnerability poses a significant risk for privilege escalation on devices using these chipsets. The issue was reserved in November 2024 and published in October 2025, but no CVSS score has been assigned to date. The vendor has identified the issue with Patch ID WCNCR00419946 and Issue ID MSV-3582, though no direct patch links are provided in the data.

For European organizations, the impact of CVE-2025-20717 depends largely on the deployment of affected MediaTek chipsets within their network infrastructure, particularly in wireless access points or embedded devices running the vulnerable SDK or openWRT versions. If exploited, the vulnerability allows local attackers with System privileges to escalate their privileges further, potentially gaining full control over the device’s firmware or operating system. This could lead to unauthorized configuration changes, persistent malware installation, or disruption of wireless services. Given the widespread use of MediaTek chipsets in consumer and enterprise-grade networking equipment, organizations relying on such hardware could face increased risk of insider threats or lateral movement by attackers who have already compromised a device. The lack of required user interaction simplifies exploitation once initial access is obtained. Additionally, compromised wireless infrastructure could undermine network confidentiality, integrity, and availability, impacting sensitive communications and operational continuity. European critical infrastructure, enterprises with large wireless deployments, and IoT-heavy environments are particularly at risk if they use affected devices without patches.

Organizations should first inventory their wireless infrastructure and embedded devices to identify the presence of affected MediaTek chipsets (MT6890, MT7615, MT7622, MT7663, MT7915, MT7916, MT7981, MT7986) and verify the firmware or SDK versions in use. Immediate mitigation involves applying vendor-supplied patches or firmware updates once available, specifically those addressing Patch ID WCNCR00419946. If patches are not yet available, consider isolating or segmenting vulnerable devices to limit access to trusted administrators only, reducing the risk of local privilege escalation. Employ strict access controls and monitoring on devices with System-level access to detect and prevent unauthorized privilege escalation attempts. Network segmentation and the use of network access control (NAC) can help contain compromised devices. Additionally, upgrading to newer openWRT releases beyond 21.02 or alternative firmware versions that do not include the vulnerable driver is advisable. Regularly monitor vendor advisories and security bulletins for updates. Finally, implement endpoint detection and response (EDR) solutions capable of identifying anomalous behavior indicative of exploitation attempts on wireless infrastructure devices.