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CVE-2026-89452
iommu/msm: Unwind probe state on registration failure
Published 2026-09-11 (37 days ago) by the Linux kernel CNA. Subsystem drivers/iommu. Debian urgency: not yet assigned.
Debian does not build this code. The per-release build detail is under "Where it lives" below.
What to do, per Debian release
Debian's own status for CVE-2026-89452 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 | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | fixedDSA-6568-1 · 2026-10-16 · text | 6.12.113-1 | Update the kernel and reboot. DSA-6568-1 shipped the fix on 2026-10-16, in 6.12.113-1. 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. |
The vulnerability
What the bug is
msm_iommu_probe() adds its devm-managed IOMMU object to qcom_iommu_devices before adding the IOMMU sysfs device and registering it with the IOMMU core. If iommu_device_sysfs_add() fails, probe returns with the object still on qcom_iommu_devices. The driver core then releases the devm allocation, leaving a dangling list entry that later list walks may dereference. If iommu_device_register() fails, the same dangling list entry remains and the sysfs device is left registered as well. Unwind the sysfs device and global list entry in reverse setup order on the corresponding failure paths.
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/msm_iommu.c
- What this is
- QUALCOMM IOMMUMAINTAINERS section matched on drivers/iommu/msm_iommu* · iommu@lists.linux.dev · Maintained
- Kernel module
- none to look for. The file would have gone into msm_iommu, and Debian does not compile it into that module, so finding msm_iommu in lsmod would say nothing about this CVE.
Check it on the machine
grep -w CONFIG_MSM_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 does not build this code. In 4 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.
- bookworm, trixie, forky, sidn
- n
- not enabled on any flavour - this release does not build the code
- Build switch
- CONFIG_MSM_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
- 2026-09-11 (37 days ago)source
- CVSS
- 8.4 high
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.20%, higher than 8.6% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- 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 |
|---|---|---|
| 4.11 | 6.12.112 | 51e37f917938 |
| 4.11 | 6.18.50 | f532401be931 |
| 4.11 | 7.2.4 | 7f7074a886c4 |
| 4.11 | 7.3 | 535a200220ca |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DSA-6568-1 | 2026-10-16 | trixie 6.12.113-1 | 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
- The bug is in msm_iommu_probe() for the Qualcomm APQ8064 platform IOMMU (compatible qcom,apq8064-iommu). It is reached only through the local platform driver core at boot or sysfs bind, not via network protocols, Bluetooth/WiFi, or a physical USB/serial endpoint.
- AC:LAttack complexity, low
- After list_add, a failed iommu_device_sysfs_add() or iommu_device_register() deterministically leaves a freed msm_iommu_dev on qcom_iommu_devices. APQ8064 has four IOMMU instances, so a later probe, of_xlate, or attach walks that list and dereferences the object with no attacker-uncontrolled race. GFP_ATOMIC allocation in insert_iommu_master during register can induce the failure.
- PR:NPrivileges required, none
- msm_iommu_probe() and later list walks in qcom_iommu_of_xlate(), find_iommu_for_dev(), and msm_iommu_attach_dev() run from the platform/IOMMU core with no capable() or credential check. On APQ8064 phones and embedded boards this happens automatically during boot or deferred probe without a user account.
- UI:NUser interaction, none
- Platform probe and subsequent IOMMU client attach/xlate run unattended during normal kernel device bring-up. No victim action such as mounting a filesystem, opening a file, or clicking a prompt is required.
- S:UScope, unchanged
- The use-after-free corrupts host kernel heap through the driver's private qcom_iommu_devices list, enabling in-kernel privilege escalation. It does not by itself escape a VM or bypass the IOMMU/DMA isolation boundary as a distinct security authority.
- C:HConfidentiality impact, high
- The dangling msm_iommu_dev stays linked after devm frees it. Subsequent list walks dereference attacker-influencable freed heap (including embedded list pointers and device state), which per kernel UAF guidance enables arbitrary kernel memory disclosure.
- I:HIntegrity impact, high
- Use-after-free of the IOMMU instance structure (list nodes, MMIO base, context-bank maps) allows heap spraying and hijack of later attach/xlate control flow, providing an arbitrary kernel write and code-execution primitive.
- A:HAvailability impact, high
- Any later walk of qcom_iommu_devices after the failed probe dereferences freed memory and can oops or panic the kernel. Kernel UAFs also crash even when not turned into a full exploit.