# CVE-2023-54239: iommufd: Check for uptr overflow

> A local attacker can trigger a kernel warning and potential denial of service via integer overflow in iommufd page mapping.

- **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:** 30 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-54239, GHSA-xcjh-8fg4-6h7p, UBUNTU-CVE-2023-54239

## What is CVE-2023-54239?

CVE-2023-54239 is a vulnerability in Linux, published on 30 Dec 2025. 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: Check for uptr overflow

syzkaller found that setting up a map with a user VA that wraps past zero
can trigger WARN_ONs, particularly from pin_user_pages weirdly returning 0
due to invalid arguments.

Prevent creating a pages with a uptr and size that would math overflow.

  WARNING: CPU: 0 PID: 518 at drivers/iommu/iommufd/pages.c:793 pfn_reader_user_pin+0x2e6/0x390
  Modules linked in:
  CPU: 0 PID: 518 Comm: repro Not tainted 6.3.0-rc2-eeac8ede1755+ #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
  RIP: 0010:pfn_reader_user_pin+0x2e6/0x390
  Code: b1 11 e9 25 fe ff ff e8 28 e4 0f ff 31 ff 48 89 de e8 2e e6 0f ff 48 85 db 74 0a e8 14 e4 0f ff e9 4d ff ff ff e8 0a e4 0f ff <0f> 0b bb f2 ff ff ff e9 3c ff ff ff e8 f9 e3 0f ff ba 01 00 00 00
  RSP: 0018:ffffc90000f9fa30 EFLAGS: 00010246
  RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff821e2b72
  RDX: 0000000000000000 RSI: ffff888014184680 RDI: 0000000000000002
  RBP: ffffc90000f9fa78 R08: 00000000000000ff R09: 0000000079de6f4e
  R10: ffffc90000f9f790 R11: ffff888014185418 R12: ffffc90000f9fc60
  R13: 0000000000000002 R14: ffff888007879800 R15: 0000000000000000
  FS:  00007f4227555740(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000020000043 CR3: 000000000e748005 CR4: 0000000000770ef0
  PKRU: 55555554
  Call Trace:
   <TASK>
   pfn_reader_next+0x14a/0x7b0
   ? interval_tree_double_span_iter_update+0x11a/0x140
   pfn_reader_first+0x140/0x1b0
   iopt_pages_rw_slow+0x71/0x280
   ? __this_cpu_preempt_check+0x20/0x30
   iopt_pages_rw_access+0x2b2/0x5b0
   iommufd_access_rw+0x19f/0x2f0
   iommufd_test+0xd11/0x16f0
   ? write_comp_data+0x2f/0x90
   iommufd_fops_ioctl+0x206/0x330
   __x64_sys_ioctl+0x10e/0x160
   ? __pfx_iommufd_fops_ioctl+0x10/0x10
   do_syscall_64+0x3b/0x90
   entry_SYSCALL_64_after_hwframe+0x72/0xdc

## Which versions are affected by CVE-2023-54239?


## How do I fix CVE-2023-54239?

Apply the vendor's patch.

## Is CVE-2023-54239 being exploited?

There is no known exploitation of CVE-2023-54239 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-54239 and fix it if it is affected.

What it is: CVE-2023-54239 is a vulnerability in Linux, published on 30 Dec 2025. 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-2023-54239 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-2023-54239/ (Markdown: https://insights.sbomify.com/CVE-2023-54239/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-54239
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-54239
- OSV: https://osv.dev/vulnerability/CVE-2023-54239

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-54239/
Summaries are generated and may contain mistakes; the official description above is the record.