CVE-2026-43097 PCI: hv: Fix double ida_free in hv_pci_probe error path
A double free vulnerability in the Linux kernel's Hyper-V PCI driver can cause a system crash during device probe failures.
- 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
What is CVE-2026-43097?
CVE-2026-43097 is a high-severity memory corruption 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:
PCI: hv: Fix double ida_free in hv_pci_probe error path
If hv_pci_probe() fails after storing the domain number in hbus->bridge->domain_nr, there is a call to free this domain_nr via pci_bus_release_emul_domain_nr(), however, during cleanup, the bridge release callback pci_release_host_bridge_dev() also frees the domain_nr causing ida_free to be called on same ID twice and triggering following warning:
ida_free called for id=28971 which is not allocated. WARNING: lib/idr.c:594 at ida_free+0xdf/0x160, CPU#0: kworker/0:2/198 Call Trace: pci_bus_release_emul_domain_nr+0x17/0x20 pci_release_host_bridge_dev+0x4b/0x60 device_release+0x3b/0xa0 kobject_put+0x8e/0x220 devm_pci_alloc_host_bridge_release+0xe/0x20 devres_release_all+0x9a/0xd0 device_unbind_cleanup+0x12/0xa0 really_probe+0x1c5/0x3f0 vmbus_add_channel_work+0x135/0x1a0
Fix this by letting pci core handle the free domain_nr and remove the explicit free called in pci-hyperv driver.
Weakness: CWE-415
Which versions are affected by CVE-2026-43097?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43097?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-43097 being exploited?
There is no known exploitation of CVE-2026-43097 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2026-43097, GHSA-qmfr-qq4j-jrfc, UBUNTU-CVE-2026-43097.