Bug 2467184 (CVE-2026-43200)

Summary: CVE-2026-43200 kernel: PCI: endpoint: Fix swapped parameters in pci_{primary/secondary}_epc_epf_unlink() functions
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's PCI endpoint functionality. Incorrect parameter handling in the pci_primary_epc_epf_unlink() and pci_secondary_epc_epf_unlink() functions allows a local user to trigger a kernel crash. This occurs when the unlink command is used in configfs, leading to a Denial of Service (DoS) for the affected system.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-05-06 13:09:20 UTC
In the Linux kernel, the following vulnerability has been resolved:

PCI: endpoint: Fix swapped parameters in pci_{primary/secondary}_epc_epf_unlink() functions

struct configfs_item_operations callbacks are defined like the following:

  int (*allow_link)(struct config_item *src, struct config_item *target);
  void (*drop_link)(struct config_item *src, struct config_item *target);

While pci_primary_epc_epf_link() and pci_secondary_epc_epf_link() specify
the parameters in the correct order, pci_primary_epc_epf_unlink() and
pci_secondary_epc_epf_unlink() specify the parameters in the wrong order,
leading to the below kernel crash when using the unlink command in
configfs:

  Unable to handle kernel paging request at virtual address 0000000300000857
  Mem abort info:
  ...
  pc : string+0x54/0x14c
  lr : vsnprintf+0x280/0x6e8
  ...
  string+0x54/0x14c
  vsnprintf+0x280/0x6e8
  vprintk_default+0x38/0x4c
  vprintk+0xc4/0xe0
  pci_epf_unbind+0xdc/0x108
  configfs_unlink+0xe0/0x208+0x44/0x74
  vfs_unlink+0x120/0x29c
  __arm64_sys_unlinkat+0x3c/0x90
  invoke_syscall+0x48/0x134
  do_el0_svc+0x1c/0x30prop.0+0xd0/0xf0

[mani: cced stable, changed commit message as per https://lore.kernel.org/linux-pci/aV9joi3jF1R6ca02@ryzen]