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CVE-2026-53281
iommu/vt-d: Avoid NULL pointer dereference or refcount corruption
Published 2026-06-26 (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-2026-53281 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 | vulnerable | 6.12.113-1 | No fix published anywhere yet, neither in Debian nor upstream for the series trixie tracks. Watch the Debian tracker page for this CVE. Advisories for trixie have historically landed a median of 11 days after publication. |
| 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
Commit 60f030f7418d ("iommu/vt-d: Avoid use of NULL after WARN_ON_ONCE") fixed a NULL pointer dereference in an unlikely situation partly. If dev_pasid is not found in the dev_pasids list, it remains NULL. However, the teardown operations are executed unconditionally, this lead to a NULL pointer dereference or refcount corruption. If the domain was never attached to this IOMMU, info will be NULL, which would cause an immediate dereference when checking --info->refcnt. Even if info is not NULL, decrementing the refcount without having removed a valid PASID might unbalance the count. This could lead to premature dropping of the refcount to 0, potentially causing a use-after-free for the remaining active devices sharing the domain. Fix it by returning early if dev_pasid is NULL, before executing the teardown operations. Issue found by AI review and suggested by Kevin Tian. https://sashiko.dev/#/patchset/20260421031347.1408890-1-zhenzhong.duan%40intel.com
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/intel/iommu.c
- What this is
- INTEL IOMMU (VT-d)MAINTAINERS section matched on drivers/iommu/intel/ · iommu@lists.linux.dev · Supported
Check it on the machine
grep -w CONFIG_INTEL_IOMMU /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, 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.
- bookwormYnot built on arm64/arm64, arm64/cloud-arm64, arm64/rt/arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, i386/686, i386/686-pae, i386/rt/686-pae, ppc64el/powerpc64le
- trixieYnot built on arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- forky, sidYnot built on arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- Y
- built in where it is built at all; some flavours do not build it
- Build switch
- CONFIG_INTEL_IOMMU
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
- 0.18%, higher than 6.9% 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 |
|---|---|---|
| 6.14 | 6.18.33 | 9022cb9ac0c2 |
| 6.14 | 7.0.10 | cdfe3c9f2c9e |
| 6.14 | 7.1 | 79ea2feb917b |
| 6.12.57 | 0 | 0 |
| 6.13.3 | 0 | 0 |
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 VT-d PASID teardown path is reached through local IOMMU/VFIO/SVA device-management operations such as iommufd/VFIO PASID attach, detach, replace, or device reset recovery. It is not reachable by network packets or adjacent radio protocols.
- AC:LAttack complexity, low
- The relevant paths are normal serialized attach/detach/reset flows and do not require winning an attacker-uncontrolled race. A PASID-capable Intel IOMMU device and suitable VFIO/SVA setup are prerequisites for the affected subsystem, but triggering the vulnerable teardown is otherwise straightforward in that environment.
- PR:LPrivileges required, low
- The attacker needs local access to a PASID-capable VFIO/iommufd or SVA-capable accelerator device node, which can be delegated to an unprivileged userspace process such as QEMU or accelerator clients. It does not inherently require real root in the initial namespace once device access is granted.
- UI:NUser interaction, none
- No separate victim action is required after the attacker controls the local device-management file descriptors. The attacker can initiate the attach/detach/close/reset-triggering sequence directly.
- S:CScope, changed
- The corruption is in IOMMU/PASID domain bookkeeping that enforces DMA isolation for devices. Premature domain refcount teardown can affect resources outside the intended device/DMA translation boundary.
- C:HConfidentiality impact, high
- Although one failure mode is a NULL dereference, the fix explicitly identifies refcount corruption that can prematurely free domain metadata and create a use-after-free for remaining active devices. Under the required conservative scoring rule, that memory corruption is treated as capable of enabling high-impact information disclosure.
- I:HIntegrity impact, high
- The same refcount corruption/use-after-free in IOMMU domain metadata can plausibly be exploited for kernel memory corruption or DMA isolation manipulation. Under the required conservative scoring rule, this supports high integrity impact.
- A:HAvailability impact, high
- If the domain was never attached to the IOMMU, `domain_detach_iommu()` can immediately dereference NULL and crash the kernel. The refcount corruption path can also lead to use-after-free crashes, so availability impact is high.