CVE-2026-45987: Linux kernel · KVM: nSVM: Sync interrupt shadow to cached vmcb12 after VMRUN of L2
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in e0377e52f3c10ee572732d11b04625b7f517a862 : update Linux kernel when convenient.
Data as of 6 Nov 2026, 16:34 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-06.
- Patch
- Available – fixed in e0377e52f3c10ee572732d11b04625b7f517a862, e39a77a9b1e17d2d831c304eafac4c41a784a0be, 1709418535a8df95532999d61b03d59975280258 +5
Exploitation evidence
Disclosed: evidence found.
CVE published 27 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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Description
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.
References
- git.kernel.org/stable/c/0c1f74d8b74d8a31751fb6ea5417e48e02c93b58 (opens in a new tab)
- git.kernel.org/stable/c/4b44aa1a134e499c4517597118378b308602a16c (opens in a new tab)
- git.kernel.org/stable/c/e39a77a9b1e17d2d831c304eafac4c41a784a0be (opens in a new tab)
- git.kernel.org/stable/c/1709418535a8df95532999d61b03d59975280258 (opens in a new tab)
- git.kernel.org/stable/c/2f950eeb27af6885416232761700b8820cae0a61 (opens in a new tab)
- git.kernel.org/stable/c/497f6af9679fc9c6ce2f438e11ed5d51b1aa8297 (opens in a new tab)
- git.kernel.org/stable/c/e0377e52f3c10ee572732d11b04625b7f517a862 (opens in a new tab)
- git.kernel.org/stable/c/03bee264f8ebfd39e0254c98e112d033a7aa9055 (opens in a new tab)