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CVE-2026-53322
vfio/pci: Clean up DMABUFs before disabling function
Published 2026-06-26 (4 months ago) by the Linux kernel CNA. Subsystem drivers/vfio. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-53322 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | not affected | 6.12.113-1 | Nothing to do. trixie never shipped the vulnerable code. |
| Debian 14forky | fixed | 7.0.10-1 | Update the kernel and reboot. Fixed in 7.0.10-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.10-1 | Update the kernel and reboot. Fixed in 7.0.10-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
On device shutdown, make vfio_pci_core_close_device() call vfio_pci_dma_buf_cleanup() before the function is disabled via vfio_pci_core_disable(). This ensures that all access via DMABUFs is revoked before the function's BARs become inaccessible. This fixes an issue where, if the function is disabled first, a tiny window exists in which the function's MSE is cleared and yet BARs could still be accessed via the DMABUF. The resources would also be freed and up for grabs by a different driver.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
drivers/vfio/pci/vfio_pci_core.c
- What this is
- VFIO DRIVERMAINTAINERS section matched on drivers/vfio/ · kvm@vger.kernel.org · Maintained
- Kernel module
- vfio_pci_core
Check it on the machine
grep -wE 'CONFIG_VFIO|CONFIG_VFIO_PCI|CONFIG_VFIO_PCI_CORE' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w vfio_pci_corePrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookwormMnot built on armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp
- trixieMnot built on armel/rpi
- forky, sidm
- M
- a module where it is built at all; some flavours do not build it
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switches
- CONFIG_VFIO, CONFIG_VFIO_PCI, CONFIG_VFIO_PCI_CORE
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-06-26 (4 months ago)source
- CVSS
- 8.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.3% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- drivers/vfio
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.19 | 7.0.10 | 4f1000a30f67 |
| 6.19 | 7.1 | d97708701434 |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The vulnerable path is reached through local VFIO device file operations and ioctls, specifically exporting a VFIO PCI BAR DMA-BUF and then closing the VFIO device fd. It is not reachable by network packets or adjacent/physical-only input.
- AC:LAttack complexity, low
- The attacker can set up the DMA-BUF/IOMMUFD mapping before triggering last-close, and the vulnerable cleanup ordering is deterministic. The P2P-capable VFIO/IOMMUFD environment is inherent to the affected feature rather than an uncontrollable exploitation condition.
- PR:LPrivileges required, low
- The attacker needs local access to an assigned VFIO PCI device and IOMMUFD/VFIO file descriptors, but normal IOMMU-backed VFIO access does not require real root once the device node is delegated. This is privileged device access, but not necessarily administrator-level privilege.
- UI:NUser interaction, none
- No separate victim action is required after the attacker has the VFIO device fd. The attacker can export the DMA-BUF and trigger teardown by closing the fd.
- S:CScope, changed
- The bug can retain DMA-BUF access to PCI BAR MMIO after VFIO has disabled/released the function and potentially after resources are reassigned, crossing the VFIO/IOMMU device-ownership boundary. This is a DMA/IOMMU isolation bypass scenario.
- C:HConfidentiality impact, high
- Stale peer-DMA access to MMIO BAR ranges can expose device registers or newly reclaimed MMIO resources outside the attacker's assigned VFIO device. In a severe reasonable deployment such as GPU, NIC, NVMe, or accelerator passthrough, this can disclose sensitive host, device, or guest data.
- I:HIntegrity impact, high
- The retained DMA-BUF mapping can allow unauthorized writes to MMIO registers or resources that should have been revoked, potentially programming device state or DMA behavior outside the attacker's ownership. That supports high integrity impact across the device isolation boundary.
- A:HAvailability impact, high
- Accessing BAR MMIO after memory space is disabled or while resources are being reclaimed can crash or wedge devices and can trigger serious platform errors on sensitive systems. Repeated local triggering can therefore cause high availability impact.