CVE-2024-27437: vfio/pci: Disable auto-enable of exclusive INTx IRQ

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-04-05 · updated 2026-10-15

Description

In the Linux kernel, the following vulnerability has been resolved: vfio/pci: Disable auto-enable of exclusive INTx IRQ Currently for devices requiring masking at the irqchip for INTx, ie. devices without DisINTx support, the IRQ is enabled in request_irq() and subsequently disabled as necessary to align with the masked status flag. This presents a window where the interrupt could fire between these events, resulting in the IRQ incrementing the disable depth twice. This would be unrecoverable for a user since the masked flag prevents nested enables through vfio. Instead, invert the logic using IRQF_NO_AUTOEN such that exclusive INTx is never auto-enabled, then unmask as required.

Affected products

Debian Linux: 10.0
Linux kernel: from 3.6 before 6.1.84; from 6.2 before 6.6.24; from 6.7 before 6.7.12; from 6.8 before 6.8.3; from 6.8.4 through 6.8.12 — fixed in 6.1.84, 6.6.24, 6.7.12, 6.8.3

How to fix

Upgrade to a fixed version: Linux kernel 6.1.84, 6.6.24, 6.7.12, 6.8.3. Check the vendor advisory for mitigations.

References

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