# CVE-2023-52659: x86/mm: Ensure input to pfn_to_kaddr() is treated as a 64-bit type

> A type casting error in the Linux kernel's pfn_to_kaddr macro causes guest crashes in SEV-SNP environments when handling high memory addresses.

- **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:** 17 May 2024
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-52659, DEBIAN-CVE-2023-52659, GHSA-jpp4-rwwf-g5qm, UBUNTU-CVE-2023-52659

## What is CVE-2023-52659?

CVE-2023-52659 is a medium-severity vulnerability in Linux kernel, published on 17 May 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:

x86/mm: Ensure input to pfn_to_kaddr() is treated as a 64-bit type

On 64-bit platforms, the pfn_to_kaddr() macro requires that the input
value is 64 bits in order to ensure that valid address bits don't get
lost when shifting that input by PAGE_SHIFT to calculate the physical
address to provide a virtual address for.

One such example is in pvalidate_pages() (used by SEV-SNP guests), where
the GFN in the struct used for page-state change requests is a 40-bit
bit-field, so attempts to pass this GFN field directly into
pfn_to_kaddr() ends up causing guest crashes when dealing with addresses
above the 1TB range due to the above.

Fix this issue with SEV-SNP guests, as well as any similar cases that
might cause issues in current/future code, by using an inline function,
instead of a macro, so that the input is implicitly cast to the
expected 64-bit input type prior to performing the shift operation.

While it might be argued that the issue is on the caller side, other
archs/macros have taken similar approaches to deal with instances like
this, such as ARM explicitly casting the input to phys_addr_t:

  e48866647b48 ("ARM: 8396/1: use phys_addr_t in pfn_to_kaddr()")

A C inline function is even better though.

[ mingo: Refined the changelog some more & added __always_inline. ]

## Which versions are affected by CVE-2023-52659?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-52659?

Apply the vendor's patch.

## Is CVE-2023-52659 being exploited?

There is no known exploitation of CVE-2023-52659 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-2023-52659 and fix it if it is affected.

What it is: CVE-2023-52659 is a medium-severity vulnerability in Linux kernel, published on 17 May 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-2023-52659 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-2023-52659/ (Markdown: https://insights.sbomify.com/CVE-2023-52659/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-52659
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-52659
- OSV: https://osv.dev/vulnerability/CVE-2023-52659

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-52659/
Summaries are generated and may contain mistakes; the official description above is the record.