CVE-2025-20710 Overview
CVE-2025-20710 is an integer overflow vulnerability in the MediaTek wireless LAN access point (WLAN AP) driver. The flaw leads to an out-of-bounds write that an adjacent-network attacker can trigger without authentication or user interaction. Successful exploitation results in remote escalation of privilege on affected MediaTek-based wireless devices. MediaTek tracks the fix as Patch ID WCNCR00418785 and Issue ID MSV-3515. The vulnerability affects multiple MediaTek Wi-Fi chipsets used in routers, access points, and OpenWrt-based devices.
Critical Impact
An unauthenticated attacker within wireless range can corrupt kernel memory in the WLAN AP driver, leading to privilege escalation with full confidentiality, integrity, and availability impact.
Affected Products
- MediaTek Software Development Kit
- MediaTek chipsets: MT6890, MT7915, MT7916, MT7981, MT7986
- OpenWrt 19.07.0 and 21.02.0
Discovery Timeline
- 2025-10-14 - CVE-2025-20710 published to NVD
- 2025-10-14 - MediaTek October 2025 Product Security Bulletin released
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-20710
Vulnerability Analysis
The vulnerability resides in the WLAN access point driver shipped with the MediaTek SDK. An attacker on an adjacent wireless network can send crafted 802.11 frames that cause an arithmetic operation in the driver to wrap around. The resulting undersized allocation or miscalculated length is then used as the bound for a write operation, producing a kernel-mode out-of-bounds write. Because the WLAN driver runs in privileged kernel context on affected MediaTek platforms, memory corruption directly translates to escalation of privilege. No authentication or user interaction is required, which lowers the barrier for exploitation against exposed access points and consumer routers.
Root Cause
The root cause is an integer overflow [CWE-190] in the WLAN AP driver. Length or count fields parsed from attacker-controlled 802.11 frames are used in arithmetic that exceeds the bounds of the underlying integer type. The overflowed value is then trusted as a size or index for a buffer operation, leading to an out-of-bounds write in adjacent kernel memory.
Attack Vector
Exploitation requires adjacent network access, meaning the attacker must be within wireless range of the vulnerable access point. The attacker transmits malformed management or data frames to the AP, triggering the integer overflow during frame processing. No credentials or user interaction are required. Successful exploitation grants kernel-level code execution on devices using affected MediaTek chipsets, including OpenWrt 19.07.0 and 21.02.0 builds shipped with the vulnerable driver.
No public proof-of-concept code is available. Technical details are described in the MediaTek October 2025 Security Bulletin.
Detection Methods for CVE-2025-20710
Indicators of Compromise
- Unexpected kernel panics, reboots, or watchdog resets on MediaTek-based access points after receiving wireless traffic.
- Anomalous 802.11 management or data frames with oversized or malformed length fields directed at the AP.
- Unusual driver log entries from the WLAN AP module referencing buffer or length errors.
Detection Strategies
- Monitor MediaTek and OpenWrt device logs (dmesg, logread) for WLAN driver faults, kernel oops messages, or repeated wireless interface restarts.
- Use wireless intrusion detection (WIDS) to flag malformed 802.11 frames and unusual frame floods targeting access points.
- Track firmware and patch level inventory across MediaTek chipsets (MT7915, MT7916, MT7981, MT7986, MT6890) to identify devices missing Patch ID WCNCR00418785.
Monitoring Recommendations
- Centralize syslog from OpenWrt and MediaTek-based devices and alert on repeated WLAN driver errors or unexpected reboots.
- Baseline normal wireless traffic patterns and alert on bursts of malformed management frames near critical access points.
- Review SNMP and management-plane telemetry for sudden configuration changes following wireless anomalies.
How to Mitigate CVE-2025-20710
Immediate Actions Required
- Apply firmware updates from device vendors that incorporate MediaTek Patch ID WCNCR00418785.
- Inventory all wireless infrastructure using MediaTek chipsets MT6890, MT7915, MT7916, MT7981, and MT7986, including OpenWrt 19.07.0 and 21.02.0 builds.
- Restrict physical and wireless proximity to vulnerable access points where patching is not yet possible.
Patch Information
MediaTek addressed the issue under Patch ID WCNCR00418785 (Issue ID MSV-3515) and published remediation guidance in the MediaTek October 2025 Security Bulletin. Downstream vendors and OpenWrt maintainers must integrate the patched WLAN AP driver into their firmware images. Operators should track vendor advisories for affected routers, access points, and embedded devices and deploy patched firmware as it becomes available.
Workarounds
- Disable the affected WLAN AP interfaces on devices that cannot receive an immediate firmware update.
- Reduce wireless transmit power and segment exposed access points to limit the radio attack surface.
- Place vulnerable access points on isolated VLANs with strict upstream filtering to contain the impact of a compromised device.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
