CVE-2026-43436
Description
A flaw was found in the Linux kernel's ALSA (Advanced Linux Sound Architecture) USB-audio driver, specifically within the Scarlett2 mixer quirk. A local attacker could exploit this vulnerability by providing a specially crafted, malformed USB descriptor. This could lead to a NULL dereference in the scarlett2_find_fc_interface() function, resulting in a system crash and a Denial of Service (DoS).
Statement
This Moderate flaw in the Linux kernel's ALSA USB-audio driver can lead to a denial of service. A local attacker with physical access to a system could trigger a NULL dereference by connecting a specially crafted USB audio device utilizing the Scarlett2 mixer quirk, causing a system crash.
Mitigation
To prevent a local attacker from exploiting this vulnerability, the `snd_usb_audio` kernel module can be blacklisted. This will prevent the module from loading and mitigate the risk of a denial of service.
1. Create a new file `/etc/modprobe.d/blacklist-snd_usb_audio.conf` with the following content:
`blacklist snd_usb_audio`
2. Regenerate the initramfs:
`# dracut -f -v`
3. Reboot the system for the changes to take effect.
Warning: Blacklisting this module will disable all USB audio functionality on the system.
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: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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