CVE-2026-45987 | KVM: nSVM: Sync interrupt shadow to cached vmcb12 after VMRUN of L2

In the Linux kernel, the following vulnerability has been resolved: KVM: nSVM: Sync interrupt shadow to cached vmcb12 after VMRUN of L2 After VMRUN in guest mode, nested_sync_control_from_vmcb02() syncs fields written by the CPU from vmcb02 to the cached vmcb12. This is because the cached vmcb12 is used as the authoritative copy of some of the controls, and is the payload when saving/restoring nested state. int_state is also written by the CPU, specifically bit 0 (i.e. SVM_INTERRUPT_SHADOW_MASK) for nested VMs, but it is not sync'd to cached vmcb12. This does not cause a problem if KVM_SET_NESTED_STATE preceeds KVM_SET_VCPU_EVENTS in the restore path, as an interrupt shadow would be correctly restored to vmcb02 (KVM_SET_VCPU_EVENTS overwrites what KVM_SET_NESTED_STATE restored in int_state). However, if KVM_SET_VCPU_EVENTS preceeds KVM_SET_NESTED_STATE, an interrupt shadow would be restored into vmcb01 instead of vmcb02. This would mostly be benign for L1 (delays an interrupt), but not for L2. For L2, the vCPU could hang (e.g. if a wakeup interrupt is delivered before a HLT that should have been in an interrupt shadow). Sync int_state to the cached vmcb12 in nested_sync_control_from_vmcb02() to avoid this problem. With that, KVM_SET_NESTED_STATE restores the correct interrupt shadow state, and if KVM_SET_VCPU_EVENTS follows it would overwrite it with the same value.

Published: 2026-05-27 Last update: 2026-06-01 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Conclusion & alert: CVE-2026-45987 is rated Low Risk (5.2/100): low exploitation likelihood (EPSS 0.02%). Mandatory action: Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-45987

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-28 0.02%

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-45987

CVSS metrics for this CVE.

No CVSS data in dataset for this CVE.

Weakness enumeration for CVE-2026-45987

GitHub Security Advisory for CVE-2026-45987

GHSA-x4f8-qj9g-g99w · Severity: unknown — In the Linux kernel, the following vulnerability has been resolved: KVM: nSVM: Sync interrupt...

OS Trackers for CVE-2026-45987

vendor priority summary link
debian not yet assigned CVE-2026-45987 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 3, open 2. https://security-tracker.debian.org/tracker/CVE-2026-45987
redhat low https://access.redhat.com/security/cve/CVE-2026-45987
suse medium CVE-2026-45987 severity moderate: SUSE including 14 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 53 product×package rows across 12 product lines (SUSE Linux Enterprise Live Patching 12 SP5, SUSE Linux Enterprise Micro 5.0, … (12 product lines)): Known Not Affected 53. https://www.suse.com/security/cve/CVE-2026-45987/
ubuntu medium CVE-2026-45987 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 891 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 508, needs-triage 224, ignored 159. https://ubuntu.com/security/CVE-2026-45987

Affected software / configurations for CVE-2026-45987

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-45987

cvelogic Threat Intelligence