# CVE-2026-53026: NFSD: fix nfs4_file access extra count in nfsd4_add_rdaccess_to_wrdeleg

> A race condition in the Linux kernel NFS server can cause a kernel bug and denial of service when stopping the service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 Jun 2026
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-53026, GHSA-5968-j93g-c79f, UBUNTU-CVE-2026-53026

## What is CVE-2026-53026?

CVE-2026-53026 is a high-severity vulnerability in Linux kernel, published on 24 Jun 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:

NFSD: fix nfs4_file access extra count in nfsd4_add_rdaccess_to_wrdeleg

In nfsd4_add_rdaccess_to_wrdeleg, if fp->fi_fds[O_RDONLY] is already
set by another thread, __nfs4_file_get_access should not be called
to increment the nfs4_file access count since that was already done
by the thread that added READ access to the file. The extra fi_access
count in nfs4_file can prevent the corresponding nfsd_file from being
freed.

When stopping nfs-server service, these extra access counts trigger a
BUG in kmem_cache_destroy() that shows nfsd_file object remaining on
__kmem_cache_shutdown.

This problem can be reproduced by running the Git project's test
suite over NFS.

## Which versions are affected by CVE-2026-53026?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53026?

Apply the vendor's patch.

## Is CVE-2026-53026 being exploited?

There is no known exploitation of CVE-2026-53026 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-2026-53026 and fix it if it is affected.

What it is: CVE-2026-53026 is a high-severity vulnerability in Linux kernel, published on 24 Jun 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-2026-53026 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-2026-53026/ (Markdown: https://insights.sbomify.com/CVE-2026-53026/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53026
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53026
- OSV: https://osv.dev/vulnerability/CVE-2026-53026

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53026/
Summaries are generated and may contain mistakes; the official description above is the record.