# CVE-2025-68292: mm/memfd: fix information leak in hugetlb folios

> Local attackers can read uninitialized kernel memory via memfd hugetlb folios, potentially exposing sensitive data.

- **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:** 16 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-68292, DEBIAN-CVE-2025-68292, GHSA-v2f5-67q3-rqpg, ROOT-OS-DEBIAN-13-CVE-2025-68292, UBUNTU-CVE-2025-68292

## What is CVE-2025-68292?

CVE-2025-68292 is a vulnerability in Linux, published on 16 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:

mm/memfd: fix information leak in hugetlb folios

When allocating hugetlb folios for memfd, three initialization steps are
missing:

1. Folios are not zeroed, leading to kernel memory disclosure to userspace
2. Folios are not marked uptodate before adding to page cache
3. hugetlb_fault_mutex is not taken before hugetlb_add_to_page_cache()

The memfd allocation path bypasses the normal page fault handler
(hugetlb_no_page) which would handle all of these initialization steps. 
This is problematic especially for udmabuf use cases where folios are
pinned and directly accessed by userspace via DMA.

Fix by matching the initialization pattern used in hugetlb_no_page():
- Zero the folio using folio_zero_user() which is optimized for huge pages
- Mark it uptodate with folio_mark_uptodate()
- Take hugetlb_fault_mutex before adding to page cache to prevent races

The folio_zero_user() change also fixes a potential security issue where
uninitialized kernel memory could be disclosed to userspace through read()
or mmap() operations on the memfd.

## Which versions are affected by CVE-2025-68292?


## How do I fix CVE-2025-68292?

Apply the vendor's patch.

## Is CVE-2025-68292 being exploited?

There is no known exploitation of CVE-2025-68292 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68292 and fix it if it is affected.

What it is: CVE-2025-68292 is a vulnerability in Linux, published on 16 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-2025-68292 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-2025-68292/ (Markdown: https://insights.sbomify.com/CVE-2025-68292/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68292
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68292
- OSV: https://osv.dev/vulnerability/CVE-2025-68292

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68292/
Summaries are generated and may contain mistakes; the official description above is the record.