Advisory Published
Updated

CVE-2024-44948: x86/mtrr: Check if fixed MTRRs exist before saving them

First published: Wed Sep 04 2024(Updated: )

In the Linux kernel, the following vulnerability has been resolved: x86/mtrr: Check if fixed MTRRs exist before saving them MTRRs have an obsolete fixed variant for fine grained caching control of the 640K-1MB region that uses separate MSRs. This fixed variant has a separate capability bit in the MTRR capability MSR. So far all x86 CPUs which support MTRR have this separate bit set, so it went unnoticed that mtrr_save_state() does not check the capability bit before accessing the fixed MTRR MSRs. Though on a CPU that does not support the fixed MTRR capability this results in a #GP. The #GP itself is harmless because the RDMSR fault is handled gracefully, but results in a WARN_ON(). Add the missing capability check to prevent this.

Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Affected SoftwareAffected VersionHow to fix
debian/linux<=5.10.223-1
5.10.226-1
6.1.123-1
6.1.119-1
6.12.11-1
6.12.12-1
debian/linux-6.1
6.1.119-1~deb11u1

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Frequently Asked Questions

  • What is the severity of CVE-2024-44948?

    CVE-2024-44948 is classified as a medium severity vulnerability.

  • How do I fix CVE-2024-44948?

    To fix CVE-2024-44948, upgrade to the patched versions of the linux package, which are 5.10.226-1, 6.1.123-1, 6.1.119-1, 6.12.11-1, or 6.12.12-1.

  • What Linux distributions are affected by CVE-2024-44948?

    CVE-2024-44948 affects Debian-based distributions that utilize the specified versions of the Linux kernel.

  • What components of the Linux kernel does CVE-2024-44948 impact?

    CVE-2024-44948 impacts the x86/mtrr component of the Linux kernel related to memory type range registers.

  • Is there a workaround for CVE-2024-44948?

    Currently, there is no known workaround for CVE-2024-44948 other than applying the appropriate kernel updates.

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