CVE-2026-68310 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: mt7915: guard HE capability lookups
mt7915_mcu_bss_he_tlv() and mt7915_mcu_sta_bfer_tlv() both run after checking HE support, then dereference the HE PHY capability returned by mt76_connac_get_he_phy_cap(). That helper can return NULL when no capability entry matches the vif type.
Fetch the capability before appending the TLV and skip the HE-specific setup when no matching capability is available.
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Analysis
by VulDB Data Team • 08/10/2026
The vulnerability in question affects the mt7915 wireless driver within the Linux kernel, specifically impacting the MediaTek mt76 wireless subsystem. This issue stems from improper handling of HE (High Efficiency) capability lookups during wireless communication setup processes. The flaw exists in two primary functions: mt7915_mcu_bss_he_tlv() and mt7915_mcu_sta_bfer_tlv(), which are responsible for managing HE PHY capabilities within the wireless network configuration. These functions execute after initial HE support checks but then directly dereference the HE PHY capability returned by mt76_connac_get_he_phy_cap() without proper validation of the returned value.
The technical root cause lies in the assumption that mt76_connac_get_he_phy_cap() will always return a valid capability structure when HE support is confirmed. However, this helper function can legitimately return NULL when no capability entry matches the specific virtual interface type being processed. This scenario occurs during complex wireless configurations where different vif types may not have corresponding HE capability entries, creating a potential null pointer dereference condition that could lead to system instability or privilege escalation.
The operational impact of this vulnerability extends beyond simple system crashes, as it represents a critical security flaw within the kernel's wireless subsystem. When null pointer dereferences occur in kernel space, they can potentially be exploited by malicious actors to escalate privileges or cause denial of service conditions that affect the entire wireless networking infrastructure. The vulnerability specifically targets the MediaTek mt7915 chipset implementation and affects systems running Linux kernels with the mt76 wireless driver stack.
This flaw aligns with CWE-476, which addresses null pointer dereference vulnerabilities in software systems. From an adversarial perspective, this vulnerability could be mapped to ATT&CK technique T1068, where attackers might exploit kernel vulnerabilities to gain elevated privileges, or T1566 for initial access through wireless network exploitation. The specific nature of the vulnerability suggests it could be leveraged in privilege escalation scenarios where an attacker gains unauthorized access to kernel-level functionality.
The recommended mitigation strategy involves modifying the driver code to fetch HE capabilities before attempting TLV (Type-Length-Value) appending operations and implementing proper NULL checking logic. This approach prevents the direct dereference of potentially null capability structures while maintaining backward compatibility with existing wireless configurations. The fix requires updating both mt7915_mcu_bss_he_tlv() and mt7915_mcu_sta_bfer_tlv() functions to validate capability entries before proceeding with HE-specific setup operations, effectively creating a robust defensive mechanism against null pointer access conditions.
The broader implications of this vulnerability highlight the importance of proper error handling in kernel space wireless drivers, particularly when dealing with hardware-specific capabilities that may not be universally available across different chipset configurations. This issue demonstrates how seemingly minor implementation oversights in capability checking can create significant security exposure points within operating system kernel modules. System administrators should prioritize applying relevant kernel updates that address this specific vulnerability while maintaining awareness of similar potential flaws in other wireless driver implementations.
Security researchers and system maintainers must recognize that this vulnerability represents a common pattern in kernel development where hardware abstraction layers fail to properly handle edge cases in capability reporting. The fix demonstrates the necessity of defensive programming practices, particularly when working with complex hardware feature sets where not all configurations will support every available capability. This vulnerability serves as a reminder of the critical importance of validating all function return values in kernel space operations, especially within wireless networking subsystems that require extensive hardware compatibility handling.
The resolution approach emphasizes the principle of early validation and proper error state management within kernel drivers. By fetching capabilities before TLV operations and implementing conditional logic to skip HE-specific setup when no matching capability exists, the driver maintains stable operation while avoiding potential exploitation vectors. This mitigation strategy not only resolves the immediate vulnerability but also establishes a more robust framework for handling similar hardware capability scenarios in future wireless driver implementations. The fix aligns with security best practices by ensuring that kernel code properly handles all possible return states from helper functions, thereby reducing the attack surface and improving overall system reliability.