CVE-2026-74325

Received Received - Intake

Use-After-Free in Linux Kernel mt76 WiFi Driver

Publication date: 2026-08-15

Last updated on: 2026-08-17

Assigner: kernel.org

Description

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).

CVSS Scores

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Meta Information

Published

2026-08-15

Last Modified

2026-08-17

Generated

2026-09-04

AI Q&A

2026-08-15

EPSS Evaluated

2026-09-03

NVD

CVE-2026-74325

EUVD

EUVD-2026-59472

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a use-after-free vulnerability in the Linux kernel's mt76 WiFi driver. It occurs when mt76_put_vif_phy_link() frees memory with kfree() while RCU readers might still be accessing it. The issue arises because rcu_assign_pointer(NULL) doesn't wait for existing RCU readers, allowing them to dereference freed memory.

Detection Guidance

This vulnerability is specific to the Linux kernel's mt76 WiFi driver and requires kernel-level inspection. Detection involves checking kernel logs for crashes or memory corruption related to mt76, particularly during WiFi operations. Commands like dmesg | grep mt76 or journalctl -k | grep mt76 may reveal issues. However, no direct detection commands are provided in the context.

Impact Analysis

This could lead to system crashes, data corruption, or privilege escalation if exploited. Attackers might trigger the use-after-free to execute arbitrary code in the kernel context. Systems using affected mt76 WiFi drivers are at risk.

Compliance Impact

This vulnerability is a memory corruption issue in the Linux kernel's WiFi driver (mt76) that could lead to use-after-free scenarios. While it does not directly impact compliance with standards like GDPR or HIPAA, such vulnerabilities can indirectly affect compliance by compromising system integrity, confidentiality, or availability of data processed on affected systems.

Mitigation Strategies

Immediate mitigation requires updating the Linux kernel to a patched version where the issue is resolved. Since the vulnerability is in the mt76 driver, ensure your kernel includes the fix for CVE-2026-74325. Check your distribution's security advisories for kernel updates and apply them promptly.

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