Linux Kernel up to 6.12.85/6.18.26/7.0.3 PCI VFIO Driver vfio_cdx_set_msi_trigger null pointer dereference

Summaryinfo

A vulnerability identified as critical has been detected in Linux Kernel up to 6.12.85/6.18.26/7.0.3. This affects the function vfio_cdx_set_msi_trigger of the component PCI VFIO Driver. Performing a manipulation results in null pointer dereference. This vulnerability is identified as CVE-2026-46034. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.12.85/6.18.26/7.0.3. This affects the function vfio_cdx_set_msi_trigger of the component PCI VFIO Driver. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: vfio/cdx: Fix NULL pointer dereference in interrupt trigger path Add validation to ensure MSI is configured before accessing cdx_irqs array in vfio_cdx_set_msi_trigger(). Without this check, userspace can trigger a NULL pointer dereference by calling VFIO_DEVICE_SET_IRQS with VFIO_IRQ_SET_DATA_BOOL or VFIO_IRQ_SET_DATA_NONE flags before ever setting up interrupts via VFIO_IRQ_SET_DATA_EVENTFD. The vfio_cdx_msi_enable() function allocates the cdx_irqs array and sets config_msi to 1 only when called through the EVENTFD path. The trigger loop (for DATA_BOOL/DATA_NONE) assumed this had already been done, but there was no enforcement of this call ordering. This matches the protection used in the PCI VFIO driver where vfio_pci_set_msi_trigger() checks irq_is() before the trigger loop.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-46034 since 05/13/2026. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 6.12.86, 6.18.27, 7.0.4 or 7.1-rc1 eliminates this vulnerability. Applying the patch 51bf7638f33aece41cb3f4cbeb942cc52950e329/5d6c349c9823eb819fed8b537b088cf38126018c/338a736aaf15e8ba3635ce20b29af5b8fc15e66a/5ea5880764cbb164afb17a62e76ca75dc371409d is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
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• 6.12.78
• 6.12.79
• 6.12.80
• 6.12.81
• 6.12.82
• 6.12.83
• 6.12.84
• 6.12.85
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
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• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3

License

• open-source

Website

• Vendor: https://www.kernel.org/

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