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CVE Record

CVE-2024-46830: KVM: x86: Acquire kvm->srcu when handling KVM_SET_VCPU_EVENTS

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Acquire kvm->srcu when handling KVM_SET_VCPU_EVENTS Grab kvm->srcu when processing KVM_SET_VCPU_EVENTS, as KVM will forcibly leave nested VMX/SVM if SMM mode is being toggled, and leaving nested VMX reads guest memory. Note, kvm_vcpu_ioctl_x86_set_vcpu_events() can also be called from KVM_RUN via sync_regs(), which already holds SRCU. I.e. trying to precisely use kvm_vcpu_srcu_read_lock() around the problematic SMM code would cause problems. Acquiring SRCU isn't all that expensive, so for simplicity, grab it unconditionally for KVM_SET_VCPU_EVENTS. ============================= WARNING: suspicious RCU usage 6.10.0-rc7-332d2c1d713e-next-vm #552 Not tainted ----------------------------- include/linux/kvm_host.h:1027 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by repro/1071: #0: ffff88811e424430 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0x7d/0x970 [kvm] stack backtrace: CPU: 15 PID: 1071 Comm: repro Not tainted 6.10.0-rc7-332d2c1d713e-next-vm #552 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: <TASK> dump_stack_lvl+0x7f/0x90 lockdep_rcu_suspicious+0x13f/0x1a0 kvm_vcpu_gfn_to_memslot+0x168/0x190 [kvm] kvm_vcpu_read_guest+0x3e/0x90 [kvm] nested_vmx_load_msr+0x6b/0x1d0 [kvm_intel] load_vmcs12_host_state+0x432/0xb40 [kvm_intel] vmx_leave_nested+0x30/0x40 [kvm_intel] kvm_vcpu_ioctl_x86_set_vcpu_events+0x15d/0x2b0 [kvm] kvm_arch_vcpu_ioctl+0x1107/0x1750 [kvm] ? mark_held_locks+0x49/0x70 ? kvm_vcpu_ioctl+0x7d/0x970 [kvm] ? kvm_vcpu_ioctl+0x497/0x970 [kvm] kvm_vcpu_ioctl+0x497/0x970 [kvm] ? lock_acquire+0xba/0x2d0 ? find_held_lock+0x2b/0x80 ? do_user_addr_fault+0x40c/0x6f0 ? lock_release+0xb7/0x270 __x64_sys_ioctl+0x82/0xb0 do_syscall_64+0x6c/0x170 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7ff11eb1b539 </TASK>

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2024-46830 is a Linux kernel KVM issue in x86 virtualization. A KVM path can read guest memory without holding the expected SRCU protection while changing virtual CPU event state. The public record does not provide CVSS, CWE, or evidence of active exploitation.

Executive priority

Treat this as a virtualization-host maintenance priority, not an emergency absent exploitation evidence. Patch KVM hosts during the next appropriate security window, faster for multi-tenant or nested-virtualization environments.

Technical view

KVM_SET_VCPU_EVENTS can force exit from nested VMX/SVM when toggling SMM mode. That path may read guest memory through nested VMX state without acquiring kvm->srcu, triggering suspicious RCU usage. The fix acquires SRCU unconditionally while processing KVM_SET_VCPU_EVENTS.

Likely exposure

Exposure is mainly Linux x86 hosts using KVM virtualization, especially where guests or management tooling can exercise vCPU event handling and nested virtualization paths. Non-KVM systems are not indicated as affected by the supplied sources.

Exploitation context

The source bundle includes a reproducer-triggered kernel warning, but no public exploit, KEV listing, or confirmed in-the-wild exploitation. Practical impact beyond unsafe RCU usage is not fully described in the provided record.

Researcher notes

The provided stack trace centers on kvm_vcpu_ioctl_x86_set_vcpu_events, vmx_leave_nested, nested_vmx_load_msr, and kvm_vcpu_read_guest. The patch rationale is synchronization correctness: acquire kvm->srcu before paths that may read guest memory.

Mitigation direction

  • Update affected Linux kernels through vendor-supported packages or stable kernel fixes.
  • Prioritize KVM hypervisors and systems offering nested virtualization.
  • Check Debian LTS guidance if using affected Debian kernel packages.
  • Restrict KVM device access to trusted virtualization management processes.
  • Monitor vendor advisories for corrected kernel versions and backports.

Validation and detection

  • Inventory Linux x86 hosts running KVM virtualization.
  • Map kernel versions to vendor advisories and listed stable commits.
  • Confirm patched kernels are deployed and running after reboot.
  • Review virtualization platforms for nested VMX/SVM exposure.
  • Check logs for KVM or RCU warnings during security review.
Prepared
Confidence
medium
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2024-46830 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
7Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxe302786233e6bc512986d007c96458ccf5ca21c7, f7e570780efc5cec9b2ed1e0472a7da14e864fdb, f7e570780efc5cec9b2ed1e0472a7da14e864fdb, f7e570780efc5cec9b2ed1e0472a7da14e864fdb, f7e570780efc5cec9b2ed1e0472a7da14e864fdb, 080dbe7e9b86a0392d8dffc00d9971792afc121f, b4c0d89c92e957ecccce12e66b63875d0cc7af7e, 5.15.19, 5.10.97, 5.16.5unaffected
LinuxLinux5.17, 0, 5.15.198, 6.1.110, 6.6.51, 6.10.10, 6.11affected
Weakness

CWE details

No CWE listed

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