# CVE-2025-38071: x86/mm: Check return value from memblock_phys_alloc_range()

> A missing return value check in the Linux kernel x86 memory management code can cause a system crash when contiguous memory is scarce.

- **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:** 18 Jun 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-63983, AZL-72713, BELL-CVE-2025-38071, DEBIAN-CVE-2025-38071, GHSA-fcf5-p95m-fc28, ROOT-OS-DEBIAN-11-CVE-2025-38071, ROOT-OS-DEBIAN-12-CVE-2025-38071, ROOT-OS-UBUNTU-2204-CVE-2025-38071, ROOT-OS-UBUNTU-2404-CVE-2025-38071, UBUNTU-CVE-2025-38071

## What is CVE-2025-38071?

CVE-2025-38071 is a medium-severity vulnerability in Debian Debian Linux, published on 18 Jun 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:

x86/mm: Check return value from memblock_phys_alloc_range()

At least with CONFIG_PHYSICAL_START=0x100000, if there is < 4 MiB of
contiguous free memory available at this point, the kernel will crash
and burn because memblock_phys_alloc_range() returns 0 on failure,
which leads memblock_phys_free() to throw the first 4 MiB of physical
memory to the wolves.

At a minimum it should fail gracefully with a meaningful diagnostic,
but in fact everything seems to work fine without the weird reserve
allocation.

## Which versions are affected by CVE-2025-38071?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-38071?

Apply the vendor's patch.

## Is CVE-2025-38071 being exploited?

There is no known exploitation of CVE-2025-38071 in the wild and no public exploit code.

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- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-38071 and fix it if it is affected.

What it is: CVE-2025-38071 is a medium-severity vulnerability in Debian Debian Linux, published on 18 Jun 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-2025-38071 in the wild and no public exploit code.

Affected product: Debian Debian 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-2025-38071/ (Markdown: https://insights.sbomify.com/CVE-2025-38071/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38071
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38071
- OSV: https://osv.dev/vulnerability/CVE-2025-38071

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38071/
Summaries are generated and may contain mistakes; the official description above is the record.