CVE-2026-46014

MEDIUM EPSS 0.7%
Published May 27, 20261mo ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Medium
Find Similar
Published May 27, 2026 1mo ago
Last Modified Jun 17, 2026 1w ago

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Add missing save/restore handling of LBR MSRs MSR_IA32_DEBUGCTLMSR and LBR MSRs are currently not enumerated by KVM_GET_MSR_INDEX_LIST, and LBR MSRs cannot be set with KVM_SET_MSRS. So save/restore is completely broken. Fix it by adding the MSRs to msrs_to_save_base, and allowing writes to LBR MSRs from userspace only (as they are read-only MSRs) if LBR virtualization is enabled. Additionally, to correctly restore L1's LBRs while L2 is running, make sure the LBRs are copied from the captured VMCB01 save area in svm_copy_vmrun_state(). Note, for VMX, this also fixes a flaw where MSR_IA32_DEBUGCTLMSR isn't reported as an MSR to save/restore. Note #2, over-reporting MSR_IA32_LASTxxx on Intel is ok, as KVM already handles unsupported reads and writes thanks to commit b5e2fec0ebc3 ("KVM: Ignore DEBUGCTL MSRs with no effect") (kvm_do_msr_access() will morph the unsupported userspace write into a nop). [sean: guard with lbrv checks, massage changelog]

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
0.7% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-667

Affected Products 2

VendorProductVersionRange
linuxlinux_kernel*≥2.6.26  –  <6.18.27
linuxlinux_kernel*≥6.19  –  <7.0.4

References 3

  • git.kernel.org https://git.kernel.org/stable/c/13a89ada5dcfc2539514c83ba5a2c61157f1ec6c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2b922a42b531a82d7881add14a7698dcdc5e1f0a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/3700f0788da6acf73b2df56690f4b201aa4aefd2
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/13a89ada5dcfc2539514c83ba5a2c61157f1ec6c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/2b922a42b531a82d7881add14a7698dcdc5e1f0a
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/3700f0788da6acf73b2df56690f4b201aa4aefd2
    Patch