Linux Kernel: information disclosure flaw under attack

What is affected

Linux Kernel is found on ordinary personal computers and phones, so this is not only a problem for companies. If you use it and have not updated since the fix was released, you are exposed.

Linux Kernel contains an out-of-bounds read vulnerability in the USB-audio driver that allows a local, privileged attacker to obtain potentially sensitive information.

What an attacker can do

This is a information disclosure flaw. It lets an attacker read data they are not supposed to see, such as memory contents, credentials or internal files. It is often the first step of a larger attack.

How it is reached

Needs access to the device or a file opened on it

Access the attacker needs

A basic user account

Does the victim have to do something?

No, works without the victim doing anything

What to do

1. Update Linux Kernel now. Open the update or "About" screen, install whatever is offered and restart the app or device, because the fix is not active until you do.
2. Turn on automatic updates so the next fix arrives without you having to look for it.
3. If your device is too old to receive this update, stop using the affected app for anything sensitive and plan a replacement.

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Vendor advisories and fixes

• lore.kernel.orglore.kernel.org/linux-cve-announce/2024122427-CVE-2024-53150-3a7d@gregkh/
• source.android.comsource.android.com/docs/security/bulletin/2025-04-01

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on April 9, 2025, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by April 30, 2025, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 1.4% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 71% of all scored vulnerabilities.

Its CVSS severity score is 7.1 out of 10 (high), as recorded in the US National Vulnerability Database.

Technical description

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Fix out of bounds reads when finding clock sources The current USB-audio driver code doesn't check bLength of each descriptor at traversing for clock descriptors. That is, when a device provides a bogus descriptor with a shorter bLength, the driver might hit out-of-bounds reads. For addressing it, this patch adds sanity checks to the validator functions for the clock descriptor traversal. When the descriptor length is shorter than expected, it's skipped in the loop. For the clock source and clock multiplier descriptors, we can just check bLength against the sizeof() of each descriptor type. OTOH, the clock selector descriptor of UAC2 and UAC3 has an array of bNrInPins elements and two more fields at its tail, hence those have to be checked in addition to the sizeof() check.