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

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-03-25 · updated 2026-06-17
Weakness: CWE-770

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.

Affected products

Linux kernel: before 4.19.193; from 4.20 before 5.4.124; from 5.5 before 5.10.42; from 5.11 before 5.12.9; 5.13-rc1, 5.13-rc2, 5.13-rc3 — fixed in 4.19.193, 5.10.42, 5.12.9, 5.4.124

How to fix

Upgrade to a fixed version: Linux kernel 4.19.193, 5.10.42, 5.12.9, 5.4.124. Check the vendor advisory for mitigations.

References

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