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CVE Record

CVE-2021-47424: i40e: Fix freeing of uninitialized misc IRQ vector

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

CVE-2021-47424 is a Linux kernel i40e driver bug that can trigger a kernel Oops during network driver setup failure. It is a reliability issue in cleanup logic, not a documented remote compromise. The available sources do not provide CVSS, CWE, or active exploitation evidence.

Executive priority

Treat this as a routine kernel reliability remediation unless affected i40e systems are business-critical. There is no source-backed evidence of exploitation, but kernel Oops conditions on network infrastructure can still create operational disruption.

Technical view

During i40e_probe(), if VSI setup fails before misc IRQ vectors are allocated, i40e_clear_interrupt_scheme() may try to free an IRQ vector that was never requested. The fix gates i40e_free_misc_vector() on the __I40E_MISC_IRQ_REQUESTED PF state, which is only set after successful misc IRQ initialization.

Likely exposure

Exposure is limited to Linux systems running affected kernels with the i40e driver involved in PF setup. The source lists Linux 4.15, 4.19.211, 5.4.153, 5.10.73, 5.14.12, and 5.15 as affected, but distribution backports may differ.

Exploitation context

The source describes a kernel Oops when driver initialization fails and then cleanup frees an already-free IRQ. There is no KEV listing and no cited source showing active exploitation, public weaponization, or remote attackability.

Researcher notes

The core condition is an error path mismatch: cleanup runs before misc IRQ allocation state is valid. Focus review on whether kernels contain the __I40E_MISC_IRQ_REQUESTED check before freeing the misc vector. Evidence is incomplete for severity scoring and exploitability.

Mitigation direction

  • Update to a vendor-supported kernel containing the referenced stable fixes.
  • Check Linux distribution advisories for the correct backported package.
  • Prioritize systems using the i40e driver in production network paths.
  • Avoid direct kernel source assumptions when using distribution kernels.

Validation and detection

  • Inventory running kernel versions and whether the i40e driver is present.
  • Confirm the vendor kernel includes the referenced stable commit or equivalent guard.
  • Review kernel logs for i40e probe failures or IRQ free warnings.
  • Validate updates first on representative systems using the same driver.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
6Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

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ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxc17401a1dd210a5f22ab1ec7c7366037c158a14c, c17401a1dd210a5f22ab1ec7c7366037c158a14c, c17401a1dd210a5f22ab1ec7c7366037c158a14c, c17401a1dd210a5f22ab1ec7c7366037c158a14c, c17401a1dd210a5f22ab1ec7c7366037c158a14cunaffected
LinuxLinux4.15, 0, 4.19.211, 5.4.153, 5.10.73, 5.14.12, 5.15affected
Weakness

CWE details

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