medium CVSS 5.5

CVE-2021-47424·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: i40e: Fix freeing of uninitialized misc IRQ vector When VSI set up failed in i40e_probe() as part of PF switch set up driver was trying to free misc IRQ vectors in i40e_clear_interrupt_scheme and produced a kernel Oops: Trying to free already-free IRQ 266 WARNING: CPU: 0 PID: 5 at kernel/irq/manage.c:1731 __free_irq+0x9a/0x300 Workqueue: events work_for_cpu_fn RIP: 0010:__free_irq+0x9a/0x300 Call Trace: ? synchronize_irq+0x3a/0xa0 free_irq+0x2e/0x60 i40e_clear_interrupt_scheme+0x53/0x190 [i40e] i40e_probe.part.108+0x134b/0x1a40 [i40e] ? kmem_cache_alloc+0x158/0x1c0 ? acpi_ut_update_ref_count.part.1+0x8e/0x345 ? acpi_ut_update_object_reference+0x15e/0x1e2 ? strstr+0x21/0x70 ? irq_get_irq_data+0xa/0x20 ? mp_check_pin_attr+0x13/0xc0 ? irq_get_irq_data+0xa/0x20 ? mp_map_pin_to_irq+0xd3/0x2f0 ? acpi_register_gsi_ioapic+0x93/0x170 ? pci_conf1_read+0xa4/0x100 ? pci_bus_read_config_word+0x49/0x70 ? do_pci_enable_device+0xcc/0x100 local_pci_probe+0x41/0x90 work_for_cpu_fn+0x16/0x20 process_one_work+0x1a7/0x360 worker_thread+0x1cf/0x390 ? create_worker+0x1a0/0x1a0 kthread+0x112/0x130 ? kthread_flush_work_fn+0x10/0x10 ret_from_fork+0x1f/0x40 The problem is that at that point misc IRQ vectors were not allocated yet and we get a call trace that driver is trying to free already free IRQ vectors. Add a check in i40e_clear_interrupt_scheme for __I40E_MISC_IRQ_REQUESTED PF state before calling i40e_free_misc_vector. This state is set only if misc IRQ vectors were properly initialized.

Severity
medium
Software
Kernel
Fixed in
5.14.12
Published
2024-05-21

Affected versions

From: 5.11

Until: 5.14.12

Fixed in: 5.14.12

How to fix this CVE

Update your Linux kernel to version 5.14.12 or later to resolve this interrupt handling vulnerability in the i40e driver. The fix adds a proper state check before attempting to free miscellaneous IRQ vectors, preventing kernel panics during failed VSI initialization. Apply the update during your next maintenance window to eliminate the risk of unexpected system crashes.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Check kernel version: uname -r — verify if version is between 5.11 and 5.14.11 (vulnerable range)
  2. Confirm i40e driver presence: lsmod | grep i40e — check if Intel i40e network driver is loaded
  3. Review kernel logs for IRQ errors: dmesg | grep -i 'Trying to free already-free IRQ' — look for the specific panic signature
  4. Verify fix applied: cat /proc/version — confirm kernel is at 5.14.12 or later

FAQ

What is CVE-2021-47424?

This vulnerability is a kernel memory management bug in the i40e Intel network driver where the interrupt cleanup routine attempts to free miscellaneous IRQ vectors that were never successfully allocated, causing a kernel oops when VSI initialization fails during driver probe.

Is CVE-2021-47424 being actively exploited?

No, this is not actively exploited. It is a kernel stability issue triggered only during specific hardware initialization failures, not a remote code execution vector.

What versions of Kernel are affected by CVE-2021-47424?

Linux kernel versions 5.11 through 5.14.11 are affected. Version 5.14.12 and later contain the fix.

How do I check if my server is vulnerable to CVE-2021-47424?

Run 'uname -r' to check your kernel version. If it falls between 5.11 and 5.14.11 and you have an i40e network adapter (check with 'lsmod | grep i40e'), your system is vulnerable.

Does Defensia detect CVE-2021-47424?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server, CVE-2021-47424 will appear in your dashboard with remediation steps.

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References

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