KVM: x86: Unconditionally recompute CR8 intercept on PPR update
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Unconditionally recompute CR8 intercept on PPR update The TPR_THRESHOLD field in the VMCS is used by VMX to induce VM exits when the guest's virtual TPR falls under the specified threshold, allowing KVM to inject previously masked interrupts. KVM handles these VM exits in handle_tpr_below_threshold(). Commit eb90f3417a0c ("KVM: vmx: speed up TPR below threshold vmexits") optimized this function by calling apic_update_ppr() instead of raising KVM_REQ_EVENT. apic_update_ppr() then raises KVM_REQ_EVENT if there is a pending, deliverable interrupt. However, if there are no new interrupts pending, apic_update_ppr() does not issue the request. Thus, kvm_lapic_update_cr8_intercept() and vmx_update_cr8_intercept() are not called before VM entry, which results in a high, stale TPR_THRESHOLD. This is problematic due to the following sentence in 28.2.1.1 "VM-Execution Control Fields" in the SDM: The following check is performed if the “use TPR shadow” VM-execution control is 1 and the “virtualize APIC accesses” and “virtual-interrupt delivery” VM-execution controls are both 0: the value of bits 3:0 of the TPR threshold VM-execution control field should not be greater than the value of bits 7:4 of VTPR. This error condition is typically not observed when KVM runs on a bare metal system because modern processors support APICv, which enables virtual-interrupt delivery, and which KVM uses when possible. This cause
CVE-2026-64513
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-64513
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "eb90f3417a0cc4880e979ccc84e41890d410ea5b",
"lessThan": "a7277b66511983b57e345c0fba21f1810fd07c0f",
"versionType": "git"
},
{
"status": "affected",
"version": "eb90f3417a0cc4880e979ccc84e41890d410ea5b",
"lessThan": "ff9c4c6428883182960cfe5c78928f0896d80ebc",
"versionType": "git"
},
{
"status": "affected",
"version": "eb90f3417a0cc4880e979ccc84e41890d410ea5b",
"lessThan": "8c8e8ac22ee17d52f9eb2bc814bca7fab90fb8df",
"versionType": "git"
},
{
"status": "affected",
"version": "eb90f3417a0cc4880e979ccc84e41890d410ea5b",
"lessThan": "bb365a506b1e6fb050c0fceaad354fe395385ef0",
"versionType": "git"
}
],
"programFiles": [
"arch/x86/kvm/lapic.c",
"arch/x86/kvm/x86.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.11"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.11",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.114",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.39",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.4",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"arch/x86/kvm/lapic.c",
"arch/x86/kvm/x86.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-64513
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #46440 · Revision 1
- Added to Heist Feed
- Publisher date