# CVE-2024-26785: iommufd: Fix protection fault in iommufd_test_syz_conv_iova

> A null pointer dereference in the Linux kernel iommufd subsystem allows local attackers to cause a system crash via a race condition.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** 4 Apr 2024
- **Updated:** 11 May 2026
- **Also known as:** AZL-59495, BELL-CVE-2024-26785, DEBIAN-CVE-2024-26785, GHSA-pjr2-pwcr-ffrh, UBUNTU-CVE-2024-26785

## What is CVE-2024-26785?

CVE-2024-26785 is a medium-severity vulnerability in Linux kernel, published on 4 Apr 2024. 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:

iommufd: Fix protection fault in iommufd_test_syz_conv_iova

Syzkaller reported the following bug:

  general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] SMP KASAN
  KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7]
  Call Trace:
   lock_acquire
   lock_acquire+0x1ce/0x4f0
   down_read+0x93/0x4a0
   iommufd_test_syz_conv_iova+0x56/0x1f0
   iommufd_test_access_rw.isra.0+0x2ec/0x390
   iommufd_test+0x1058/0x1e30
   iommufd_fops_ioctl+0x381/0x510
   vfs_ioctl
   __do_sys_ioctl
   __se_sys_ioctl
   __x64_sys_ioctl+0x170/0x1e0
   do_syscall_x64
   do_syscall_64+0x71/0x140

This is because the new iommufd_access_change_ioas() sets access->ioas to
NULL during its process, so the lock might be gone in a concurrent racing
context.

Fix this by doing the same access->ioas sanity as iommufd_access_rw() and
iommufd_access_pin_pages() functions do.

Weakness: CWE-120 (Buffer Copy without Checking Size of Input)

## Which versions are affected by CVE-2024-26785?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-26785?

Apply the vendor's patch.

## Is CVE-2024-26785 being exploited?

There is no known exploitation of CVE-2024-26785 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-26785 and fix it if it is affected.

What it is: CVE-2024-26785 is a medium-severity vulnerability in Linux kernel, published on 4 Apr 2024. 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-2024-26785 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2024-26785/ (Markdown: https://insights.sbomify.com/CVE-2024-26785/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-26785
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-26785
- OSV: https://osv.dev/vulnerability/CVE-2024-26785

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-26785/
Summaries are generated and may contain mistakes; the official description above is the record.