Look up another CVE · open CVE-2026-90241 in the interactive tracker
CVE-2026-90241
iommu/vt-d: Tear down scalable-mode context on probe failure
Published 2026-09-17 (31 days ago) by the Linux kernel CNA. Subsystem drivers/iommu. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-90241 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 | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
intel_pasid_setup_sm_context() walks a PCI device’s DMA aliases via pci_for_each_dma_alias() and programs a scalable-mode context entry for each RID. For a device with a dma_alias_mask, the callback is invoked once for the device’s own RID and once for each alias bit, all with the same pci_dev, so device_pasid_table_setup() runs for multiple RIDs. pci_for_each_dma_alias() stops at the first callback error. Therefore, a failure partway through the walk can leave context entries for already processed RIDs present and still pointing to the device’s PASID table. On this error path, intel_iommu_probe_device() currently jumps directly to intel_pasid_free_table(), which frees the PASID table without first tearing down those context entries. The IOMMU may then walk a present context entry whose PASID table pointer references freed memory. intel_iommu_release_device() already performs teardown before freeing the table. Apply the same ordering on the probe failure path. device_pasid_table_teardown() safely handles RIDs that were never programmed: iommu_context_addr() returns NULL when no context table has been allocated, and clearing the Present bit of an already non-present entry is a no-op. So unwind is safe for both the alias that failed and any aliases not yet reached.
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
- bookworm · linux-6.12Ynot built on arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k
- 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
- 2026-09-17 (31 days ago)source
- CVSS
- 8.2 high
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.17%, higher than 6.0% 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 |
|---|---|---|
| 6.9 | 6.12.110 | 25ac85a9747c |
| 6.9 | 6.18.52 | d0e978ced742 |
| 6.9 | 7.2.6 | db5daf25f754 |
| 6.9 | 7.3 | c509fb73a109 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
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
- intel_iommu_probe_device() is called from iommu_probe_device() on BUS_NOTIFY_ADD_DEVICE in iommu_bus_notifier; the Present context entries are programmed by intel_pasid_setup_sm_context() via pci_for_each_dma_alias() during that host probe, not by a remote protocol payload.
- AC:LAttack complexity, low
- device_pasid_table_setup() can succeed for an earlier dma_alias_mask RID then fail when iommu_context_addr(..., true) GFP_ATOMIC-allocates the other scalable-mode context table; pci_for_each_dma_alias() stops, and the free_table path leaves those Present entries indefinitely, so a local attacker who induces that -ENOMEM does not need an uncontrolled race.
- PR:HPrivileges required, high
- The free_table error path is reached only by adding or re-probing a PCI device into intel_iommu_probe_device(), which requires init-namespace CAP_SYS_ADMIN (pci-sysfs rescan is mode 0200 via dev_rescan_store, likewise remove/SR-IOV); user namespaces cannot trigger this IOMMU probe.
- UI:NUser interaction, none
- The attacker themselves issues the PCI add/rescan (or equivalent hotplug they control) that runs intel_iommu_probe_device(); no separate victim action such as mounting a filesystem is required.
- S:CScope, changed
- context_entry_set_pasid_table() leaves Present scalable-mode context entries pointing at the device PASID directory; intel_pasid_free_table() then frees that directory without teardown, so VT-d can translate DMA against reused host pages and bypass the IOMMU device/host isolation boundary.
- C:HConfidentiality impact, high
- A Present context entry whose PASID table was freed by intel_pasid_free_table() is a translation-table use-after-free; reclaiming those pages lets a device DMA-read host physical memory outside its assigned domain.
- I:HIntegrity impact, high
- The same stale PASID-table pointer lets the device DMA-write host memory outside its domain, turning the probe-path UAF into an arbitrary write and potential control-flow hijack across the IOMMU boundary.
- A:HAvailability impact, high
- Hardware walks of the freed PASID directory cause DMAR faults, kernel oops/panic, or host hangs; the unfixed free_table path is a use-after-free, which is A:H.