[USN-7489-2] Linux kernel (Real-time) vulnerability

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Ubuntu Security Notice USN-7489-2
May 07, 2025

linux-realtime vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 24.10

Summary:

The system could be made to crash under certain conditions.

Software Description:
- linux-realtime: Linux kernel for Real-time systems

Details:

A security issue was discovered in the Linux kernel.
An attacker could possibly use this to compromise the system.
This update corrects flaws in the following subsystems:
- Timer subsystem;
(CVE-2025-21813)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 24.10
linux-image-6.11.0-1009-realtime 6.11.0-1009.9
Available with Ubuntu Pro
linux-image-realtime 6.11.0-1009.9
Available with Ubuntu Pro

After a standard system update you need to reboot your computer to make
all the necessary changes.

ATTENTION: Due to an unavoidable ABI change the kernel updates have
been given a new version number, which requires you to recompile and
reinstall all third party kernel modules you might have installed.
Unless you manually uninstalled the standard kernel metapackages
(e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual,
linux-powerpc), a standard system upgrade will automatically perform
this as well.

References:
https://ubuntu.com/security/notices/USN-7489-2
https://ubuntu.com/security/notices/USN-7489-1
CVE-2025-21813

Package Information:
https://launchpad.net/ubuntu/+source/linux-realtime/6.11.0-1009.9