# CVE-2026-46268: PCI/P2PDMA: Fix p2pmem_alloc_mmap() warning condition

> A logic error in the Linux kernel PCI/P2PDMA driver triggers a warning when debug VM options are enabled, potentially causing system instability.

- **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:** 3 Jun 2026
- **Updated:** 3 Jun 2026
- **Also known as:** BELL-CVE-2026-46268, DEBIAN-CVE-2026-46268, GHSA-9f46-h8mj-93v5, UBUNTU-CVE-2026-46268

## What is CVE-2026-46268?

CVE-2026-46268 is a medium-severity vulnerability in Linux kernel, published on 3 Jun 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:

PCI/P2PDMA: Fix p2pmem_alloc_mmap() warning condition

Commit b7e282378773 has already changed the initial page refcount of
p2pdma page from one to zero, however, in p2pmem_alloc_mmap() it uses
"VM_WARN_ON_ONCE_PAGE(!page_ref_count(page))" to assert the initial page
refcount should not be zero and the following will be reported when
CONFIG_DEBUG_VM is enabled:

  page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x380400000
  flags: 0x20000000002000(reserved|node=0|zone=4)
  raw: 0020000000002000 ff1100015e3ab440 0000000000000000 0000000000000000
  raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
  page dumped because: VM_WARN_ON_ONCE_PAGE(!page_ref_count(page))
  ------------[ cut here ]------------
  WARNING: CPU: 5 PID: 449 at drivers/pci/p2pdma.c:240 p2pmem_alloc_mmap+0x83a/0xa60

Fix by using "page_ref_count(page)" as the assertion condition.

## Which versions are affected by CVE-2026-46268?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-46268?

Apply the vendor's patch.

## Is CVE-2026-46268 being exploited?

There is no known exploitation of CVE-2026-46268 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-2026-46268 and fix it if it is affected.

What it is: CVE-2026-46268 is a medium-severity vulnerability in Linux kernel, published on 3 Jun 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-2026-46268 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-2026-46268/ (Markdown: https://insights.sbomify.com/CVE-2026-46268/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46268
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46268
- OSV: https://osv.dev/vulnerability/CVE-2026-46268

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46268/
Summaries are generated and may contain mistakes; the official description above is the record.