CVE-2021-47170 USB: usbfs: Don't WARN about excessively large memory allocations

What is CVE-2021-47170?

CVE-2021-47170 is a medium-severity denial of service vulnerability in Linux kernel, published on 25 Mar 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

USB: usbfs: Don't WARN about excessively large memory allocations

Syzbot found that the kernel generates a WARNing if the user tries to submit a bulk transfer through usbfs with a buffer that is way too large. This isn't a bug in the kernel; it's merely an invalid request from the user and the usbfs code does handle it correctly.

In theory the same thing can happen with async transfers, or with the packet descriptor table for isochronous transfers.

To prevent the MM subsystem from complaining about these bad allocation requests, add the __GFP_NOWARN flag to the kmalloc calls for these buffers.

Weakness: CWE-770

Which versions are affected by CVE-2021-47170?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2021-47170?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2021-47170 being exploited?

There is no known exploitation of CVE-2021-47170 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-2021-47170, GHSA-c673-578f-v4xm, UBUNTU-CVE-2021-47170.