Bug 2466985 (CVE-2026-43097)

Summary: CVE-2026-43097 kernel: PCI: hv: Fix double ida_free in hv_pci_probe error path
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: low    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's PCI Hyper-V driver. During error handling, a specific resource identifier can be inadvertently freed twice. This double free vulnerability can lead to memory corruption, potentially causing system instability and a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-05-06 10:01:52 UTC 
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.
Comment 1 Alexander B 2026-05-06 15:12:32 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050620-CVE-2026-43097-5b0d@gregkh/T