# CVE-2026-64216: netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()

> A use-after-free vulnerability in the Linux kernel netfs subsystem allows attackers to potentially execute arbitrary code or escalate privileges.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Jul 2026
- **Updated:** 27 Aug 2026
- **Also known as:** BELL-CVE-2026-64216, DEBIAN-CVE-2026-64216, GHSA-wm9r-84gr-484q, ROOT-OS-DEBIAN-13-CVE-2026-64216, ROOT-OS-UBUNTU-2204-CVE-2026-64216, UBUNTU-CVE-2026-64216

## What is CVE-2026-64216?

CVE-2026-64216 is a critical use after free vulnerability in Linux kernel, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()

netfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it
is wanting to unlock and compares that to rreq->no_unlock_folio so that it
doesn't unlock a folio being read for netfs_perform_write() or
netfs_write_begin().

However, given that netfs_unlock_abandoned_read_pages() is called _after_
NETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to
dereference is the one specified by ->no_unlock_folio as ownership
immediately reverts to the caller.

Fix this by storing the folio pointer instead and using that rather than
the index.  Also fix netfs_unlock_read_folio() where the same applies.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-64216?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64216?

Apply the vendor's patch.

## Is CVE-2026-64216 being exploited?

There is no known exploitation of CVE-2026-64216 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-2026-64216 and fix it if it is affected.

What it is: CVE-2026-64216 is a critical use after free vulnerability in Linux kernel, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-64216 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-2026-64216/ (Markdown: https://insights.sbomify.com/CVE-2026-64216/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64216
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64216
- OSV: https://osv.dev/vulnerability/CVE-2026-64216

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64216/
Summaries are generated and may contain mistakes; the official description above is the record.