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CVE-2026-52952
iommu: Fix WARN_ON in __iommu_group_set_domain_nofail() due to reset
Published 2026-06-24 (4 months ago) by the Linux kernel CNA. Subsystem drivers/iommu. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-52952 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
In __iommu_group_set_domain_internal(), concurrent domain attachments are rejected when any device in the group is recovering. This is necessary to fence concurrent attachments to a multi-device group where devices might share the same RID due to PCI DMA alias quirks, but triggers the WARN_ON in __iommu_group_set_domain_nofail(). Other IOMMU_SET_DOMAIN_MUST_SUCCEED callers in detach/teardown paths, such as __iommu_group_set_core_domain and __iommu_release_dma_ownership, should not be rejected, as the domain would be freed anyway in these nofail paths while group->domain is still pointing to it. So pci_dev_reset_iommu_done() could trigger a UAF when re-attaching group->domain. Honor the IOMMU_SET_DOMAIN_MUST_SUCCEED flag, allowing the callers through the group->recovery_cnt fence, so as to update the group->domain pointer. Instead add a gdev->blocked check in the device iteration loop, to prevent any concurrent per-device detachment.
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/iommu/iommu.c
- What this is
- IOMMU SUBSYSTEMMAINTAINERS section matched on drivers/iommu/ · iommu@lists.linux.dev · Maintained
Check it on the machine
grep -w CONFIG_IOMMU_API /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.
Show whether Debian builds this, per release
Debian builds this code. Every release below compiles the affected file into the kernels it ships.
- bookworm, trixie, forky, sidy
- y
- built into the kernel image on every flavour - only a patch removes it
- Build switch
- CONFIG_IOMMU_API
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
- 2026-06-24 (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
- 0.18%, higher than 6.8% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- drivers/iommu
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 7.0 | 7.0.10 | 8fc289e809f3 |
| 7.0 | 7.1 | 5474e6e17a26 |
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 IOMMU recovery path is reached through local PCI/VFIO/IOMMUFD operations such as device reset and domain attach/detach, not by remote packets or physical insertion.
- AC:LAttack complexity, low
- A caller with access to the VFIO/IOMMUFD device can create the reset window and concurrently detach/release the domain; the race window is attacker-influenced and does not depend on rare external conditions.
- PR:LPrivileges required, low
- Exploitation requires local access to an assigned VFIO/IOMMUFD-capable device or equivalent device node permissions, but not necessarily full init-namespace root once the device is delegated.
- UI:NUser interaction, none
- No victim action is needed after the attacker has the local device access; the attacker can issue the reset and detach operations directly.
- S:CScope, changed
- The stale freed IOMMU domain can affect DMA/IOMMU isolation, allowing impact beyond the attacker's assigned device/IOMMU context and into host-protected resources.
- C:HConfidentiality impact, high
- The bug can leave `group->domain` pointing to a freed IOMMU domain and then reattach through it, a use-after-free that can plausibly be shaped into disclosure of protected host memory.
- I:HIntegrity impact, high
- Reusing a freed IOMMU domain during device reattachment can corrupt IOMMU state or subvert DMA mappings, giving a plausible path to arbitrary modification of protected memory.
- A:HAvailability impact, high
- At minimum the stale domain dereference and WARN/UAF path can crash or destabilize the kernel during reset recovery.