# CVE-2026-89449: iommu: Fix dev_iommu memory leak when device_add fails in iommu_mock_device_add

> A memory leak in the Linux kernel IOMMU subsystem allows local attackers to exhaust system memory via ioctl calls, leading to denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-89449, DEBIAN-CVE-2026-89449, GHSA-3365-g9v5-8jg9, UBUNTU-CVE-2026-89449

## What is CVE-2026-89449?

CVE-2026-89449 is a memory corruption vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

iommu: Fix dev_iommu memory leak when device_add fails in iommu_mock_device_add

iommu_mock_device_add() first calls iommu_fwspec_init(), which on
success allocates both dev->iommu (via dev_iommu_get()) and
dev->iommu->fwspec. If the subsequent device_add(dev) call fails,
the error path only calls iommu_fwspec_free(dev), which frees
fwspec but leaves dev->iommu still allocated.

This triggers the following kmemleak report when fuzzing with Syzkaller:

BUG: memory leak
unreferenced object 0xffff888011e0a200 (size 192):
  comm "syz.1.1695", pid 24885, jiffies 4295222527
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 ad 4e ad de  .............N..
    ff ff ff ff 00 00 00 00 ff ff ff ff ff ff ff ff  ................
  backtrace (crc 25df5bb3):
    kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
    slab_post_alloc_hook mm/slub.c:4575 [inline]
    slab_alloc_node mm/slub.c:4899 [inline]
    __kmalloc_cache_noprof+0x47a/0x710 mm/slub.c:5415
    kmalloc_noprof include/linux/slab.h:950 [inline]
    kzalloc_noprof include/linux/slab.h:1188 [inline]
    dev_iommu_get+0x10c/0x1a0 drivers/iommu/iommu.c:408
    iommu_fwspec_init+0x288/0x4d0 drivers/iommu/iommu.c:3087
    iommu_mock_device_add+0x46/0xb0 drivers/iommu/iommu.c:385
    mock_dev_create drivers/iommu/iommufd/selftest.c:1025 [inline]
    iommufd_test_mock_domain drivers/iommu/iommufd/selftest.c:1066 [inline]
    iommufd_test+0x2f8a/0x6190 drivers/iommu/iommufd/selftest.c:2072
    iommufd_fops_ioctl+0x367/0x540 drivers/iommu/iommufd/main.c:533
    vfs_ioctl fs/ioctl.c:51 [inline]
    __do_sys_ioctl fs/ioctl.c:597 [inline]
    __se_sys_ioctl fs/ioctl.c:583 [inline]
    __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
    do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
    do_syscall_64+0x116/0x800 arch/x86/entry/syscall_64.c:94
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

Fix this by calling dev_iommu_free(dev) instead of iommu_fwspec_free(dev)
in the device_add() failure path. dev_iommu_free() frees both fwspec
and the outer dev_iommu struct and clears dev->iommu.

## Which versions are affected by CVE-2026-89449?


## How do I fix CVE-2026-89449?

Apply the vendor's patch.

## Is CVE-2026-89449 being exploited?

There is no known exploitation of CVE-2026-89449 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89449 and fix it if it is affected.

What it is: CVE-2026-89449 is a memory corruption vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-89449 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-89449/ (Markdown: https://insights.sbomify.com/CVE-2026-89449/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89449
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89449
- OSV: https://osv.dev/vulnerability/CVE-2026-89449

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89449/
Summaries are generated and may contain mistakes; the official description above is the record.