CVE-2026-53248net: airoha: Fix use-after-free in metadata dst teardown

Official description

In the Linux kernel, the following vulnerability has been resolved: net: airoha: Fix use-after-free in metadata dst teardown airoha_metadata_dst_free() runs 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, an 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.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/6f829e2c17a53a35321268339cd252aff6d6d723
• https://git.kernel.org/stable/c/4b5a574e033e66d2131eff1c18feef8d8643c67e
• https://git.kernel.org/stable/c/b38cae85d1c45ff189d7ecb6ac36f41cdc3d84d0