CVE-2026-53247
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk40th percentile - higher than 40% of all known CVEs
Summary
In the Linux kernel's mtk_eth_soc network driver, a use-after-free vulnerability was found. The mtk_free_dev() function calls metadata_dst_free() which immediately frees the metadata_dst memory, bypassing the RCU grace period. In the RX path, skb_dst_set_noref() sets a non-refcounted pointer, which can lead to accessing freed memory if any skb still holds that pointer during driver teardown.
Risk Assessment
An attacker could exploit this vulnerability to achieve remote code execution or cause a denial of service (DoS) by sending specially crafted network packets that trigger access to already freed memory in the driver.
Recommendation
Immediately update the Linux kernel to a version containing the fix that replaces metadata_dst_free() with dst_release(), ensuring proper memory deallocation with RCU grace period.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: net: ethernet: mtk_eth_soc: Fix use-after-free in metadata dst teardown mtk_free_dev() calls metadata_dst_free() which frees the metadata_dst with kfree() immediately, bypassing the RCU grace period. In the RX path, skb_dst_set_noref() sets a non-refcounted pointer from the skb to the metadata_dst. This function requires RCU read-side protection and the dst must remain valid until all RCU readers complete. Since metadata_dst_free() calls kfree() directly, a use-after-free can occur if any skb still holds a noref pointer to the dst when the driver tears it down. Replace metadata_dst_free() with dst_release() which properly goes through the refcount path: when the refcount drops to zero, it schedules the actual free via call_rcu_hurry(), ensuring all RCU readers have completed before the memory is freed.