CVE-2025-38513

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> wifi: zd1211rw: Fix potential NULL pointer dereference in zd_mac_tx_to_dev()<br /> <br /> There is a potential NULL pointer dereference in zd_mac_tx_to_dev(). For<br /> example, the following is possible:<br /> <br /> T0 T1<br /> zd_mac_tx_to_dev()<br /> /* len == skb_queue_len(q) */<br /> while (len &gt; ZD_MAC_MAX_ACK_WAITERS) {<br /> <br /> filter_ack()<br /> spin_lock_irqsave(&amp;q-&gt;lock, flags);<br /> /* position == skb_queue_len(q) */<br /> for (i=1; itype == NL80211_IFTYPE_AP)<br /> skb = __skb_dequeue(q);<br /> spin_unlock_irqrestore(&amp;q-&gt;lock, flags);<br /> <br /> skb_dequeue() -&gt; NULL<br /> <br /> Since there is a small gap between checking skb queue length and skb being<br /> unconditionally dequeued in zd_mac_tx_to_dev(), skb_dequeue() can return NULL.<br /> Then the pointer is passed to zd_mac_tx_status() where it is dereferenced.<br /> <br /> In order to avoid potential NULL pointer dereference due to situations like<br /> above, check if skb is not NULL before passing it to zd_mac_tx_status().<br /> <br /> Found by Linux Verification Center (linuxtesting.org) with SVACE.