CVE-2025-21917: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: usb: renesas_usbhs: Flush the notify_hotplug_work When performing continuous unbind/bind operations on the USB drivers available on the Renesas RZ/G2L SoC, a kernel crash with the message "Unable to handle kernel NULL pointer dereference at virtual address" may occur. This issue points to the usbhsc_notify_hotplug() function. Flush the delayed work to avoid its execution when driver resources are unavailable.

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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	3.0 — 5.4.291
linux	linux_kernel	5.5 — 5.10.235
linux	linux_kernel	5.11 — 5.15.179
linux	linux_kernel	5.16 — 6.1.131
linux	linux_kernel	6.2 — 6.6.83
linux	linux_kernel	6.7 — 6.12.19
linux	linux_kernel	6.13 — 6.13.7
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/3248c1f833f924246cb98ce7da4569133c1b2292 https://git.kernel.org/stable/c/394965f90454d6f00fe11879142b720c6c1a872e https://git.kernel.org/stable/c/4ca078084cdd5f32d533311d6a0b63a60dcadd41 https://git.kernel.org/stable/c/4cd847a7b630a85493d0294ad9542c21aafaa246 https://git.kernel.org/stable/c/552ca6b87e3778f3dd5b87842f95138162e16c82 https://git.kernel.org/stable/c/830818c8e70c0364e377f0c243b28061ef7967eb https://git.kernel.org/stable/c/d50f5c0cd949593eb9a3d822b34d7b50046a06b7 https://git.kernel.org/stable/c/e5aac1c9b2974636db7ce796ffa6de88fa08335e

Other References

https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html

Frequently Asked Questions

What is CVE-2025-21917? +

In the Linux kernel, the following vulnerability has been resolved: usb: renesas_usbhs: Flush the notify_hotplug_work When performing continuous unbind/bind operations on the USB drivers available on the Renesas RZ/G2L SoC, a kernel crash with the message "Unable to handle kernel NULL pointer dereference at virtual address" may occur. This issue points to the usbhsc_notify_hotplug() function. Flush the delayed work to avoid its execution when driver resources are unavailable. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-21917? +

CVE-2025-21917 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-2025-21917? +

CVE-2025-21917 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-21917? +

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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