CVE-2021-47267 usb: fix various gadget panics on 10gbps cabling

What is CVE-2021-47267?

CVE-2021-47267 is a medium-severity vulnerability in Linux kernel, published on 21 May 2024. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

usb: fix various gadget panics on 10gbps cabling

usb_assign_descriptors() is called with 5 parameters, the last 4 of which are the usb_descriptor_header for: full-speed (USB1.1 - 12Mbps [including USB1.0 low-speed @ 1.5Mbps), high-speed (USB2.0 - 480Mbps), super-speed (USB3.0 - 5Gbps), super-speed-plus (USB3.1 - 10Gbps).

The differences between full/high/super-speed descriptors are usually substantial (due to changes in the maximum usb block size from 64 to 512 to 1024 bytes and other differences in the specs), while the difference between 5 and 10Gbps descriptors may be as little as nothing (in many cases the same tuning is simply good enough).

However if a gadget driver calls usb_assign_descriptors() with a NULL descriptor for super-speed-plus and is then used on a max 10gbps configuration, the kernel will crash with a null pointer dereference, when a 10gbps capable device port + cable + host port combination shows up. (This wouldn't happen if the gadget max-speed was set to 5gbps, but it of course defaults to the maximum, and there's no real reason to artificially limit it)

The fix is to simply use the 5gbps descriptor as the 10gbps descriptor, if a 10gbps descriptor wasn't provided.

Obviously this won't fix the problem if the 5gbps descriptor is also NULL, but such cases can't be so trivially solved (and any such gadgets are unlikely to be used with USB3 ports any way).

Weakness: CWE-476

Which versions are affected by CVE-2021-47267?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2021-47267?

Apply the vendor's patch.

Is CVE-2021-47267 being exploited?

There is no known exploitation of CVE-2021-47267 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2021-47267, GHSA-wf38-7v3f-5mjp, UBUNTU-CVE-2021-47267.