CVE-2025-40269

A flaw was found in the ALSA USB audio driver of the Linux kernel. This vulnerability, a buffer overflow, occurs when the size of the Pulse-Code Modulation (PCM) stream data packets exceeds the maximum allowed by the USB descriptor. A local attacker could exploit this by providing specially crafted USB audio device parameters, causing the PCM transfer buffer to overflow. This could lead to sensitive information disclosure and potentially result in a denial of service (DoS).

This vulnerability is rated Moderate rather than Important because exploitation requires either physical access to attach a malicious peripheral or access to an emulated USB interface in virtualized environments. Typical Red Hat Enterprise Linux server deployments do not utilize USB audio hardware or expose physical ports to untrusted individuals, though desktop workstations and virtual machines with USB passthrough remain exposed. If a rogue device is connected, the resulting memory corruption could trigger a kernel crash or disclose sensitive information.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent the snd_usb_audio kernel module from loading if USB audio functionality is not required. Create a file /etc/modprobe.d/disable-snd-usb-audio.conf with the following content: install snd_usb_audio /bin/true After creating the file, a system reboot is required for the changes to take effect. This action will disable all USB audio device functionality.