CVE-2024-44948

x86/mtrr: Check if fixed MTRRs exist before saving them

State: Published
Severity: Not scored
Published: Sep 4, 2024
Updated: Oct 15, 2026
Reserved: Aug 21, 2024

Description

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.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 34f36e6ee5bd7eff8b2adcd9fcaef369f752d82eAffected 2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 06c1de44d378ec5439db17bf476507d68589bfe9Affected 2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 450b6b22acdaac67a18eaf5ed498421ffcf10051Affected 2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before ca7d00c5656d1791e28369919e3e10febe9c3b16Affected 2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 8aa79dfb216b865e96ff890bc4ea71650f9bc8d7Affected 2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 8a90d3fc7c24608548d3a750671f9dac21d1a462Affected 2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 388f1c954019f253a8383f7eb733f38d541e10b6Affected 2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 919f18f961c03d6694aa726c514184f2311a4614Affected
LinuxLinux	2.6.22Affected before 2.6.22Not affected 4.19.320 through 4.19.Not affected 5.4.282 through 5.4.Not affected 5.10.224 through 5.10.Not affected 5.15.165 through 5.15.Not affected 6.1.105 through 6.1.Not affected 6.6.46 through 6.6.Not affected 6.10.5 through 6.10.*Not affected 6.11 and laterNot affected

Product

Versions

LinuxLinux

2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 34f36e6ee5bd7eff8b2adcd9fcaef369f752d82eAffected
2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 06c1de44d378ec5439db17bf476507d68589bfe9Affected
2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 450b6b22acdaac67a18eaf5ed498421ffcf10051Affected
2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before ca7d00c5656d1791e28369919e3e10febe9c3b16Affected
2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 8aa79dfb216b865e96ff890bc4ea71650f9bc8d7Affected
2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 8a90d3fc7c24608548d3a750671f9dac21d1a462Affected
2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 388f1c954019f253a8383f7eb733f38d541e10b6Affected
2b1f6278d77c1f2f669346fc2bb48012b5e9495a to before 919f18f961c03d6694aa726c514184f2311a4614Affected

LinuxLinux

2.6.22Affected
before 2.6.22Not affected
4.19.320 through 4.19.*Not affected
5.4.282 through 5.4.*Not affected
5.10.224 through 5.10.*Not affected
5.15.165 through 5.15.*Not affected
6.1.105 through 6.1.*Not affected
6.6.46 through 6.6.*Not affected
6.10.5 through 6.10.*Not affected
6.11 and laterNot affected

References

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