CVE-2025-38513 Information

Aug 17, 2025 cve

Description

In the Linux kernel the following vulnerability has been resolved:

wifi: zd1211rw: Fix potential NULL pointer dereference in zd_mac_tx_to_dev()

There is a potential NULL pointer dereference in zd_mac_tx_to_dev(). For example the following is possible:

	T0			    		T1

zd_mac_tx_to_dev() / len == skb_queue_len(q) / while (len > ZD_MAC_MAX_ACK_WAITERS)

				  filter_ack()
				    spin_lock_irqsave(&q->lock flags);
				    / position == skb_queue_len(q) /
				    for (i=1; i<position; i++)
			    	      skb = __skb_dequeue(q)

				    if (mac->type == NL80211_IFTYPE_AP)
				      skb = __skb_dequeue(q);
				    spin_unlock_irqrestore(&q->lock flags);

skb_dequeue() -> NULL

Since there is a small gap between checking skb queue length and skb being unconditionally dequeued in zd_mac_tx_to_dev() skb_dequeue() can return NULL. Then the pointer is passed to zd_mac_tx_status() where it is dereferenced.

In order to avoid potential NULL pointer dereference due to situations like above check if skb is not NULL before passing it to zd_mac_tx_status().

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Reference

https://git.kernel.org/stable/c/014c34dc132015c4f918ada4982e952947ac1047 https://git.kernel.org/stable/c/5420de65efbeb6503bcf1d43451c9df67ad60298 https://git.kernel.org/stable/c/602b4eb2f25668de15de69860ec99caf65b3684d https://git.kernel.org/stable/c/74b1ec9f5d627d2bdd5e5b6f3f81c23317657023 https://git.kernel.org/stable/c/adf08c96b963c7cd7ec1ee1c0c556228d9bedaae https://git.kernel.org/stable/c/b24f65c184540dfb967479320ecf7e8c2e9220dc https://git.kernel.org/stable/c/c1958270de947604cc6de05fc96dbba256b49cf0 https://git.kernel.org/stable/c/fcd9c923b58e86501450b9b442ccc7ce4a8d0fda

CNNVD-202508-1929 (Published: 2025-08-16)

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