# 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.

- **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:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2026-43097, GHSA-qmfr-qq4j-jrfc, UBUNTU-CVE-2026-43097

## 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 (Double Free)

## Which versions are affected by CVE-2026-43097?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43097?

Apply the vendor's patch.

## 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

- [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-2026-43097 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-43097 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-2026-43097/ (Markdown: https://insights.sbomify.com/CVE-2026-43097/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43097
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43097
- OSV: https://osv.dev/vulnerability/CVE-2026-43097

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43097/
Summaries are generated and may contain mistakes; the official description above is the record.