CVE-2025-38513: debian linux Null Dereference — Fix

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.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	2.6.25 — 5.4.296
linux	linux_kernel	5.5 — 5.10.240
linux	linux_kernel	5.11 — 5.15.189
linux	linux_kernel	5.16 — 6.1.146
linux	linux_kernel	6.2 — 6.6.99
linux	linux_kernel	6.7 — 6.12.39
linux	linux_kernel	6.13 — 6.15.7
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
debian	debian_linux	All

References

Advisories & Patches

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

Other References

https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html

Frequently Asked Questions

What is CVE-2025-38513? +

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. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-38513? +

CVE-2025-38513 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-38513? +

CVE-2025-38513 affects products from debian, linux, specifically: debian_linux, linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-38513? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2025-38513