CVE-2026-43429
Description
A flaw was found in the Linux kernel's usbtmc driver. A local user can exploit this vulnerability by providing arbitrarily long timeout values through an ioctl command. This can cause the kernel thread to hang indefinitely, leading to a Denial of Service (DoS) condition.
Statement
Moderate: A flaw in the Linux kernel's usbtmc driver allows a local attacker to cause a denial of service. By supplying an excessively long timeout value via an ioctl command, a local user can force a kernel thread to hang indefinitely, impacting system availability.
Mitigation
To mitigate this vulnerability, prevent the `usbtmc` kernel module from loading if USB Test and Measurement Class devices are not in use. This can be achieved by blacklisting the module.
Create a file named `/etc/modprobe.d/blacklist-usbtmc.conf` with the following content:
blacklist usbtmcAfter creating the file, regenerate the initramfs to ensure the blacklist is applied on boot:
For RHEL 8 and 9:
`sudo dracut -f -v`
For RHEL 7:
`sudo dracut -f`
A system reboot is required for the changes to take effect. This mitigation may impact functionality that relies on USBTMC devices.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
When allocating resources without limits, an attacker could prevent other systems, applications, or processes from accessing the same type of resource. It can be easy for an attacker to consume many resources by rapidly making many requests or causing larger resources to be used than is needed.
Frequently Asked Questions
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