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CVE-2025-40038

In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Skip fastpath emulation on VM-Exit if next RIP isn't valid Skip the WRMSR and HLT fastpat…

Published Oct 28, 2025 · corrected/updated Oct 15, 2026 · evidence confidence high

In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Skip fastpath emulation on VM-Exit if next RIP isn't valid Skip the WRMSR and HLT fastpaths in SVM's VM-Exit handler if the next RIP isn't valid, e.g. because KVM is running with nrips=false. SVM must decode and emulate to skip the instruction if the CPU doesn't provide the next RIP, and getting the instruction bytes to decode requires reading guest memory. Reading guest memory through the emulator can fault, i.e. can sleep, which is disallowed since the fastpath handlers run with IRQs disabled. BUG: sleeping function called from invalid context at ./include/linux/uaccess.h:106 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 32611, name: qemu preempt_count: 1, expected: 0 INFO: lockdep is turned off. irq event stamp: 30580 hardirqs last enabled at (30579): [ ] vcpu_run+0x1787/0x1db0 [kvm] hardirqs last disabled at (30580): [ ] __schedule+0x1e2/0xed0 softirqs last enabled at (30570): [ ] fpu_swap_kvm_fpstate+0x44/0x210 softirqs last disabled at (30568): [ ] fpu_swap_kvm_fpstate+0x44/0x210 CPU: 298 UID: 0 PID: 32611 Comm: qemu Tainted: G U 6.16.0-smp--e6c618b51cfe-sleep #782 NONE Tainted: [U]=USER Hardware name: Google Astoria-Turin/astoria, BIOS 0.20241223.2-0 01/17/2025 Call Trace: dump_stack_lvl+0x7d/0xb0 __might_resched+0x271/0x290 __might_fault+0x28/0x80 kvm_vcpu_read_guest_page+0x8d/0xc0 [kvm] kvm_fetch_guest_virt+0x92/0xc0 [kvm] __do_insn_fetch_bytes+0xf3/0x1e0 [kvm] x86_decode_insn+0xd1/0x1010 [kvm] x86_emulate_instruction+0x105/0x810 [kvm] __svm_skip_emulated_instruction+0xc4/0x140 [kvm_amd] handle_fastpath_invd+0xc4/0x1a0 [kvm] vcpu_run+0x11a1/0x1db0 [kvm] kvm_arch_vcpu_ioctl_run+0x5cc/0x730 [kvm] kvm_vcpu_ioctl+0x578/0x6a0 [kvm] __se_sys_ioctl+0x6d/0xb0 do_syscall_64+0x8a/0x2c0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f479d57a94b Note, this is essentially a reapply of commit 5c30e8101e8d ("KVM: SVM: Skip WRMSR fastpath on VM-Exit if next RIP isn't valid"), but

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2025-40038 is a high public vulnerability record for this product. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether this product is in your estate, then compare installed versions with the affected ranges. Affected version ranges have not been ingested yet. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 7.1, EPSS 0.2%. It is not currently listed in the CISA Known Exploited catalog. Sources contributing to this record: cve_org, epss, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Not listed as known exploited in CISA KEV. Not in the CISA KEV catalog.

  • Patch and remediation

    No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 28, 2025 · NIST NVD

    Detected

    In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Skip fastpath emulation on VM-Exit if next RIP isn't valid Skip the WRMSR and HLT fastpaths in SVM's VM-Exit handler if the next RIP isn't valid, e.g. because KVM is running with nrips=false. SVM must decode and emulate to skip the instruction if the CPU doesn't provide the next RIP, and getting the instruction bytes to

  2. Oct 15, 2026 · NIST NVD

    Updated

    In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Skip fastpath emulation on VM-Exit if next RIP isn't valid Skip the WRMSR and HLT fastpaths in SVM's VM-Exit handler if the next RIP isn't valid, e.g. because KVM is running with nrips=false. SVM must decode and emulate to skip the instruction if the CPU doesn't provide the next RIP, and getting the instruction bytes to

Sources

  • CVE.orgVulnerability recordCVE-2025-40038

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-40038

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2025-40038

    In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Skip fastpath emulation on VM-Exit if next RIP isn't valid Skip the WRMSR and HLT fastpaths in SVM's VM-Exit handler if the next RIP isn't valid, e.g. because KVM is running with nrips=false. SVM mus

    nvd.nist.gov

References