# CVE-2026-43214: KVM: x86: Add SRCU protection for reading PDPTRs in __get_sregs2()

> A race condition in KVM x86 PDPTR reading lacks SRCU protection, potentially causing kernel warnings or instability during guest memory access.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 May 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-43214, DEBIAN-CVE-2026-43214, GHSA-5c3f-mcw3-6q2w, ROOT-OS-UBUNTU-2204-CVE-2026-43214, ROOT-OS-UBUNTU-2404-CVE-2026-43214, UBUNTU-CVE-2026-43214

## What is CVE-2026-43214?

CVE-2026-43214 is a high-severity vulnerability in Linux kernel, published on 6 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

KVM: x86: Add SRCU protection for reading PDPTRs in __get_sregs2()

Add SRCU read-side protection when reading PDPTR registers in
__get_sregs2().

Reading PDPTRs may trigger access to guest memory:
kvm_pdptr_read() -> svm_cache_reg() -> load_pdptrs() ->
kvm_vcpu_read_guest_page() -> kvm_vcpu_gfn_to_memslot()

kvm_vcpu_gfn_to_memslot() dereferences memslots via __kvm_memslots(),
which uses srcu_dereference_check() and requires either kvm->srcu or
kvm->slots_lock to be held. Currently only vcpu->mutex is held,
triggering lockdep warning:

=============================
WARNING: suspicious RCU usage in kvm_vcpu_gfn_to_memslot
6.12.59+ #3 Not tainted

include/linux/kvm_host.h:1062 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
1 lock held by syz.5.1717/15100:
 #0: ff1100002f4b00b0 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0x1d5/0x1590

Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0xf0/0x120 lib/dump_stack.c:120
 lockdep_rcu_suspicious+0x1e3/0x270 kernel/locking/lockdep.c:6824
 __kvm_memslots include/linux/kvm_host.h:1062 [inline]
 __kvm_memslots include/linux/kvm_host.h:1059 [inline]
 kvm_vcpu_memslots include/linux/kvm_host.h:1076 [inline]
 kvm_vcpu_gfn_to_memslot+0x518/0x5e0 virt/kvm/kvm_main.c:2617
 kvm_vcpu_read_guest_page+0x27/0x50 virt/kvm/kvm_main.c:3302
 load_pdptrs+0xff/0x4b0 arch/x86/kvm/x86.c:1065
 svm_cache_reg+0x1c9/0x230 arch/x86/kvm/svm/svm.c:1688
 kvm_pdptr_read arch/x86/kvm/kvm_cache_regs.h:141 [inline]
 __get_sregs2 arch/x86/kvm/x86.c:11784 [inline]
 kvm_arch_vcpu_ioctl+0x3e20/0x4aa0 arch/x86/kvm/x86.c:6279
 kvm_vcpu_ioctl+0x856/0x1590 virt/kvm/kvm_main.c:4663
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xbd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-43214?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43214?

Apply the vendor's patch.

## Is CVE-2026-43214 being exploited?

There is no known exploitation of CVE-2026-43214 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43214 and fix it if it is affected.

What it is: CVE-2026-43214 is a high-severity vulnerability in Linux kernel, published on 6 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-43214 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-43214/ (Markdown: https://insights.sbomify.com/CVE-2026-43214/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43214
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43214
- OSV: https://osv.dev/vulnerability/CVE-2026-43214

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43214/
Summaries are generated and may contain mistakes; the official description above is the record.