CVE-2026-74681
Received Received - Intake

USB Buffer Size Mismatch in Linux Kernel USBIO Driver

Publication date: 2026-08-22

Last updated on: 2026-08-22

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: usb: misc: usbio: check ibuf_len against rxbuf_len in bulk msg ibuf_len is the bulk IN (receive) buffer size, but the EMSGSIZE check in usbio_bulk_msg() compares it against txbuf_len — the bulk OUT endpoint size. Both are taken independently from different endpoints in usbio_probe(), so the check is wrong when they differ. Use rxbuf_len for the IN direction. This matches the buffer that actually holds the response data.

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Meta Information

Published
2026-08-22
Last Modified
2026-08-22
Generated
2026-08-22
AI Q&A
2026-08-22
EPSS Evaluated
N/A
NVD
CVE-2026-74681
EUVD
EUVD-2026-64368

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is in the Linux kernel's USB misc driver (usbio). It involves a buffer size check error where the code incorrectly compares the receive buffer size (ibuf_len) against the transmit buffer size (txbuf_len) instead of the receive buffer size (rxbuf_len) for bulk IN messages. This mismatch can lead to buffer overflows or incorrect data handling during USB communication.

Detection Guidance

This vulnerability is specific to the Linux kernel's USB subsystem and does not have a direct network detection method. To check if your system is affected, verify the kernel version and whether it includes the vulnerable usbio driver. Use commands like 'uname -a' to check the kernel version and 'lsmod | grep usbio' to see if the driver is loaded.

Impact Analysis

This vulnerability could allow an attacker to cause a buffer overflow or memory corruption in the Linux kernel when processing USB bulk IN messages. This might lead to system crashes, denial of service, or potentially privilege escalation if exploited. Users of affected Linux systems with USB devices using the usbio driver could be impacted.

Mitigation Strategies

Update the Linux kernel to a patched version that resolves this issue. Check with your distribution's package manager for updates, such as 'apt upgrade' for Debian-based systems or 'yum update' for RHEL-based systems. If a patch is not yet available, consider disabling the usbio driver if it is not required.

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