# CVE-2026-53398: NFSD: Fix SECINFO_NO_NAME decode error cleanup

> A flaw in the Linux kernel NFSD component allows a denial of service via improper cleanup of uninitialized variables during truncated XDR decoding.

- **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:** 19 Jul 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-53398, DEBIAN-CVE-2026-53398, GHSA-hfvv-wwwp-6wgr, ROOT-OS-DEBIAN-11-CVE-2026-53398, ROOT-OS-UBUNTU-2204-CVE-2026-53398, UBUNTU-CVE-2026-53398

## What is CVE-2026-53398?

CVE-2026-53398 is a critical vulnerability in Linux kernel, published on 19 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:

NFSD: Fix SECINFO_NO_NAME decode error cleanup

nfsd4_decode_secinfo_no_name() currently initializes sin_exp after
decoding sin_style. If the XDR stream is truncated, the decoder returns
nfserr_bad_xdr before sin_exp is initialized.

Since commit 3fdc54646234 ("NFSD: Reduce amount of struct
nfsd4_compoundargs that needs clearing"), the inline iops array is not
cleared between RPC calls. A failed SECINFO_NO_NAME decode can therefore
leave sin_exp holding stale union contents from a previous operation.

The error response path still invokes nfsd4_secinfo_no_name_release(),
which calls exp_put() on a non-NULL sin_exp.

Initialize sin_exp before the first failable decode step, matching
nfsd4_decode_secinfo().

Weakness: CWE-665 (Improper Initialization)

## Which versions are affected by CVE-2026-53398?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53398?

Apply the vendor's patch.

## Is CVE-2026-53398 being exploited?

There is no known exploitation of CVE-2026-53398 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-2026-53398 and fix it if it is affected.

What it is: CVE-2026-53398 is a critical vulnerability in Linux kernel, published on 19 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-2026-53398 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-2026-53398/ (Markdown: https://insights.sbomify.com/CVE-2026-53398/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53398
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53398
- OSV: https://osv.dev/vulnerability/CVE-2026-53398

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53398/
Summaries are generated and may contain mistakes; the official description above is the record.