CVE-2026-74322 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: mt7996: Fix possible NULL pointer dereference in mt7996_mac_write_txwi_80211()
For injected frames (e.g. via radiotap), mac80211 can pass info->control.vif = NULL, as explicitly noted in struct ieee80211_tx_info. Check vif pointer before executing ieee80211_vif_is_mld() in mt7996_mac_write_txwi_80211 routine in order to avoid a possible NULL pointer dereference.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability identified in the Linux kernel's mt76 wireless driver module represents a critical null pointer dereference condition that could lead to system instability or potential privilege escalation. This issue specifically affects the mt7996_mac_write_txwi_80211 function within the MediaTek MT7996 wireless chipset driver, where improper validation of virtual interface pointers creates an exploitable code path. The flaw occurs during the processing of injected frames transmitted through radiotap interfaces, which are commonly used for wireless packet injection and monitoring purposes in security testing and network analysis.
The technical root cause stems from inadequate input validation within the mac80211 subsystem integration where the driver routine fails to properly verify that the virtual interface pointer remains valid before invoking the ieee80211_vif_is_mld() function. According to the ieee80211_tx_info structure documentation, the control.vif field can legitimately be set to NULL for injected frames, yet the mt7996 driver implementation does not account for this possibility in its code execution flow. This null pointer dereference vulnerability aligns with CWE-476 which specifically addresses null pointer dereference conditions in software implementations.
The operational impact of this vulnerability extends beyond simple system crashes, potentially enabling denial of service attacks against wireless networking services or creating opportunities for privilege escalation depending on the execution context. When malicious actors inject frames through radiotap interfaces with NULL virtual interface pointers, the kernel enters an undefined state upon attempting to dereference the null pointer during txwi_80211 frame processing. This condition could be exploited in scenarios where wireless network services are critical to system operations or when combined with other vulnerabilities in the networking stack.
Mitigation strategies should prioritize immediate patch application from trusted sources including official Linux kernel releases and distribution repositories, as the fix involves straightforward pointer validation logic that prevents the null dereference without affecting normal wireless operation. System administrators should also implement monitoring for unusual wireless frame injection patterns and consider restricting radiotap interface usage to authorized administrative domains only. The vulnerability demonstrates the importance of defensive programming practices in kernel space code and aligns with ATT&CK technique T1059.007 for command and scripting interpreter execution, as it could enable attackers to manipulate wireless networking components through crafted frame injection attacks. Additional security measures include implementing proper input validation at all subsystem boundaries and conducting regular security audits of kernel modules that interface with user-space applications through wireless frameworks.