Look up another CVE · open CVE-2026-90425 in the interactive tracker
CVE-2026-90425
iommu/tegra241-cmdqv: Require exactly one Stream ID for a vSID
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-2026-90425 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 | 7.2.6-1 | 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. |
The vulnerability
What the bug is
tegra241_vintf_init_vsid() maps a guest vSID to a single physical Stream ID taken from master->streams[0], and only warns when the device does not have exactly one stream. A device with several streams gets only its first one mapped, so a guest vSID invalidation cannot reach the others' ATC and IOTLB entries; a device with none makes master->streams a ZERO_SIZE_PTR, read out of bounds. Reject the mapping with -EOPNOTSUPP if master->num_streams is not one.
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/arm/arm-smmu-v3/tegra241-cmdqv.c
- What this is
- TEGRA IOMMU DRIVERSMAINTAINERS section matched on drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c · linux-tegra@vger.kernel.org · Supported
Check it on the machine
grep -wE 'CONFIG_ARM_SMMU_V3|CONFIG_TEGRA241_CMDQV' /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 does not build this code in 3 releases. The build rule could not be established for 1 release, so nothing is claimed about those.
- bookworm?
- trixie, forky, sidn
- ?
- not established - no Makefile entry for the affected file
- n
- not enabled on any flavour - this release does not build the code
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
- Build switches
- CONFIG_ARM_SMMU_V3, CONFIG_TEGRA241_CMDQV
- 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
- 2026-09-17 (31 days 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
- 0.17%, higher than 6.3% 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 |
|---|---|---|
| 6.17 | 6.18.52 | 9b37afb2d34d |
| 6.17 | 7.2.6 | 0b139ec4641c |
| 6.17 | 7.3 | fb292bfc9be9 |
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
- tegra241_vintf_init_vsid() is reached only via iommufd_fops_ioctl() dispatching IOMMU_VDEVICE_ALLOC to iommufd_vdevice_alloc_ioctl() after VFIO_DEVICE_BIND_IOMMUFD. master->num_streams comes from the bound device's IORT/DT fwspec, not from a network protocol message.
- AC:LAttack complexity, low
- Once a CMDQV master is bound, IOMMU_VDEVICE_ALLOC always does writel(master->streams[0].id, SID_REPLACE). pci_for_each_dma_alias (iort_pci_iommu_init) yields num_streams>1 and maps only the first SID; num_streams==0 reads ZERO_SIZE_PTR. The attacker issues that ioctl; no race or uninfluenced layout is required.
- PR:LPrivileges required, low
- iommufd_fops_open() and iommufd_vdevice_alloc_ioctl() have no capable() check (/dev/iommu 0660). A tenant or unprivileged QEMU user granted VFIO access on NVIDIA Grace can VFIO_DEVICE_BIND_IOMMUFD, IOMMU_VIOMMU_ALLOC type TEGRA241_CMDQV, and IOMMU_VDEVICE_ALLOC without init-namespace root.
- UI:NUser interaction, none
- The attacker opens iommufd, binds the assigned device, allocates the TEGRA241_CMDQV vIOMMU and vDEVICE, then issues guest ATC_INV on the mmap'd VCMDQ themselves. No separate victim action such as mounting a filesystem is required.
- S:CScope, changed
- tegra241_vintf_init_vsid() programs SID_REPLACE/SID_MATCH only for master->streams[0], so CMDQV HW rewrite of guest ATC_INV (no VMEXIT) and arm_vsmmu_cache_invalidate cannot reach the other streams' ATC/IOTLB. That is an IOMMU/DMA boundary bypass: stale translations let device DMA reach host memory outside the guest domain.
- C:HConfidentiality impact, high
- After a guest IOVA unmap, stale ATC/IOTLB entries on the unprogrammed physical SIDs let the passthrough device DMA-read recycled host pages. That is an arbitrary host-memory disclosure through the IOMMU, not a bounded kernel-pointer leak.
- I:HIntegrity impact, high
- The same stale translations allow DMA writes into recycled host pages, and programming only one of several SIDs leaves ATC_INV operating on the wrong Stream ID, corrupting IOMMU translation state with an arbitrary write suitable for control-flow hijack.
- A:HAvailability impact, high
- When fwspec->num_ids is 0, arm_smmu_insert_master() sets master->streams to ZERO_SIZE_PTR ((void *)16) and tegra241_vintf_init_vsid() dereferences streams[0].id, which slab.h documents as a distinct access fault/oops; missed invalidations also let hostile DMA panic the host.