CVE-2025-20740 is a vulnerability classified as CWE-367, a time-of-check to time-of-use (TOCTOU) race condition found in the WLAN STA driver of several MediaTek Wi-Fi chipsets, specifically MT7902, MT7920, MT7921, MT7922, MT7925, and MT7927. The flaw exists due to a race condition that leads to an out-of-bounds read in the driver code. This occurs when the driver checks certain data or state and then uses it without proper synchronization, allowing the data to change between the check and use phases. The consequence is a local information disclosure vulnerability, where an attacker with user-level execution privileges can read memory outside intended bounds, potentially leaking sensitive information. Exploitation does not require any user interaction, increasing the risk if an attacker gains local access. The vulnerability affects devices running NB SDK release 3.7 and earlier. Although no public exploits are known, the flaw's nature suggests it could be leveraged in targeted attacks or combined with other vulnerabilities. The issue is significant because MediaTek chipsets are widely used in consumer and enterprise wireless devices, including laptops, IoT devices, and embedded systems. The lack of a CVSS score means severity must be assessed based on impact and exploitability factors. The vulnerability primarily threatens confidentiality due to information disclosure, with integrity and availability less impacted. The root cause is a synchronization failure in the driver code, which MediaTek has acknowledged and assigned Patch ID WCNCR00435337. Organizations using affected hardware should prioritize patching once updates are released and monitor for any emerging exploits.

For European organizations, the primary impact of CVE-2025-20740 is the potential local disclosure of sensitive information through exploitation of the race condition in MediaTek WLAN drivers. This could lead to leakage of credentials, cryptographic keys, or other confidential data stored in memory, undermining data confidentiality. Since the vulnerability requires local user privileges but no user interaction, it poses a risk in environments where untrusted users have local access or where malware could escalate privileges. This is particularly relevant for enterprises with shared workstations, public access terminals, or IoT deployments using affected chipsets. The vulnerability could facilitate lateral movement or privilege escalation chains in targeted attacks. Additionally, compromised wireless drivers could impact network stability or security posture indirectly. Given the widespread use of MediaTek chipsets in consumer and enterprise devices across Europe, the vulnerability could affect a broad range of sectors including finance, healthcare, manufacturing, and government. The lack of known exploits currently limits immediate risk, but the potential for future exploitation necessitates proactive mitigation. Failure to address this vulnerability could result in regulatory compliance issues under GDPR if sensitive personal data is exposed.

1. Apply official patches from MediaTek as soon as they become available, specifically addressing Patch ID WCNCR00435337. 2. For devices where patches are not yet available, restrict local user access to trusted personnel only and enforce strict user privilege management to minimize the risk of exploitation. 3. Implement endpoint detection and response (EDR) solutions to monitor for anomalous behavior related to driver exploitation or memory access patterns. 4. Conduct regular firmware and driver inventory audits to identify devices using affected MediaTek chipsets and NB SDK versions 3.7 or earlier. 5. Employ network segmentation to isolate devices with vulnerable wireless hardware from critical systems. 6. Use application whitelisting and privilege restriction to prevent unauthorized code execution that could leverage this vulnerability. 7. Educate IT staff and users about the risks of local privilege misuse and the importance of applying security updates promptly. 8. Monitor threat intelligence feeds for any emerging exploits targeting this vulnerability to enable rapid incident response. 9. Coordinate with device vendors and suppliers to ensure timely updates and support for affected hardware. 10. Consider temporary mitigation such as disabling affected wireless interfaces in high-risk environments until patches are deployed.