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Advisory severityMedium5.5Vendor: LowRed Hat Linux

Medium [CVE-2026-64430] Avoid calling pci_irq_vector from hardirq context

This medium-severity Red Hat Linux advisory covers CVE-2026-64430.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-64430 Source published Source updated

VulniPulse record published Record updated

CVE-2026-64430
Affected products & platforms
Red Hat LinuxUnclassified
Open source advisory

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Summary

In the Linux kernel, the following vulnerability has been resolved: NTB: epf: Avoid calling pci_irq_vector() from hardirq context ntb_epf_vec_isr() calls pci_irq_vector() in hardirq context to derive the vector number. pci_irq_vector() calls msi_get_virq() that takes a mutex and can therefore trigger "scheduling while atomic" splats: BUG: scheduling while atomic: kworker/u33:0/55/0x00010001...

Call trace:... schedule+0x38/0x110 schedule_preempt_disabled+0x28/0x50 __mutex_lock.constprop.0+0x848/0x908 __mutex_lock_slowpath+0x18/0x30 mutex_lock+0x4c/0x60 msi_domain_get_virq+0xe8/0x138 pci_irq_vector+0x2c/0x60 ntb_epf_vec_isr+0x28/0x120 [ntb_hw_epf] __handle_irq_event_percpu+0x70/0x3a8 handle_irq_event+0x48/0x100 handle_edge_irq+0x100/0x1c8...

Cache the Linux IRQ number for vector 0 when vectors are allocated and use it as a base in the ISR. Running the ISR in a threaded IRQ handler would also avoid the problem, but that would be unnecessary here.

A flaw was found in the Linux kernel's Non-Transparent Bridge (NTB) Endpoint Function (EPF) component. During critical interrupt processing, the system attempts to acquire a lock, which is an operation not permitted in this context.

This improper handling can lead to a system crash, resulting in a denial of service for the affected system. Red Hat severity: Low — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.

Official advisory · medium-confidence parse· fetched 1 month ago·verify at source

Fixed versions

No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.

Official advisory · medium-confidence parse· fetched 1 month ago·verify at source

Mitigation

The source record does not include mitigation steps. That does not mean no fix exists. Read the vendor advisory below for the authoritative guidance.

Official advisory · medium-confidence parse· fetched 1 month ago·verify at source

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