CVE-2026-74325
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
In the Linux kernel, the mt76 WiFi driver has a use-after-free issue in mt76_put_vif_phy_link(). The function frees the offchannel mlink with kfree(), but rcu_assign_pointer does not wait for existing RCU readers who may still hold the pointer. The TX path can dereference freed memory.
Risk Assessment
Use-after-free can lead to system crashes or unpredictable behavior, especially during heavy network traffic.
Recommendation
Apply the kernel patch that uses kfree_rcu() instead of kfree() to ensure safe freeing after all RCU readers are done.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: use kfree_rcu for offchannel link in mt76_put_vif_phy_link mt76_put_vif_phy_link() frees the offchannel mlink with plain kfree() after rcu_assign_pointer(NULL). However, rcu_assign_pointer only prevents future RCU readers from obtaining the pointer -- it does not wait for existing readers that already hold it via rcu_dereference. The TX datapath (e.g. mt7996_mac_write_txwi) dereferences mlink->wcid and mlink->idx under rcu_read_lock. If a TX softirq obtained the pointer via rcu_dereference just before the NULL assignment, it will dereference freed memory after the kfree. struct mt76_vif_link already contains an rcu_head field that is unused at this free site -- a developer oversight, since the adjacent kfree_rcu_mightsleep call for rx_sc in the same function shows the pattern was understood. Replace kfree(mlink) with kfree_rcu(mlink, rcu_head).