CVE-2021-47476: comedi: ni_usb6501: fix NULL-deref in command paths

Severity: medium (CVSS 4.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-22 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: comedi: ni_usb6501: fix NULL-deref in command paths The driver uses endpoint-sized USB transfer buffers but had no sanity checks on the sizes. This can lead to zero-size-pointer dereferences or overflowed transfer buffers in ni6501_port_command() and ni6501_counter_command() if a (malicious) device has smaller max-packet sizes than expected (or when doing descriptor fuzz testing). Add the missing sanity checks to probe().

Affected products

Linux kernel: from 3.18 before 4.4.292; from 4.5 before 4.9.290; from 4.10 before 4.14.255; from 4.15 before 4.19.217; from 4.20 before 5.4.159; from 5.5 before 5.10.79 — fixed in 4.14.255, 4.19.217, 4.4.292, 4.9.290, 5.10.79, 5.14.18

How to fix

Upgrade to a fixed version: Linux kernel 4.14.255, 4.19.217, 4.4.292, 4.9.290. Check the vendor advisory for mitigations.

References

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