# CVE-2026-99052: selinux: preserve NATIVE_LABELS on already-initialized sb in set_mnt_opts


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 23 Oct 2026
- **Updated:** 23 Oct 2026
- **Also known as:** AZL-110930, BELL-CVE-2026-99052, DEBIAN-CVE-2026-99052, GHSA-8mqq-3q6f-v2w5, UBUNTU-CVE-2026-99052

## What is CVE-2026-99052?

CVE-2026-99052 is a vulnerability in Linux, published on 23 Oct 2026. 

### Official description

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

selinux: preserve NATIVE_LABELS on already-initialized sb in set_mnt_opts

When an NFSv4 filesystem exported with security_label is mounted a
second time, sget_fc() returns the existing superblock and
nfs_get_root() calls security_sb_set_mnt_opts() again on it. Since the
superblock is already SB_INITIALIZED, selinux_set_mnt_opts() takes an
early exit without setting SECURITY_LSM_NATIVE_LABELS in
*set_kern_flags. nfs_get_root() then sees kflags without
SECURITY_LSM_NATIVE_LABELS set and clears NFS_CAP_SECURITY_LABEL on
the shared nfs_server, silently disabling per-file labeling for both
the new and the original mount.

Commit 3815a245b501 ("security/selinux: fix SECURITY_LSM_NATIVE_LABELS
on reused superblock") fixed the same problem in
selinux_sb_clone_mnt_opts().  The reused-superblock path for a plain
second mount now goes through sb_set_mnt_opts rather than
sb_clone_mnt_opts, so it needs the same treatment: on both
SE_SBINITIALIZED early exits, set SECURITY_LSM_NATIVE_LABELS in
*set_kern_flags when the superblock was already using
SECURITY_FS_USE_NATVE.

## Which versions are affected by CVE-2026-99052?


## How do I fix CVE-2026-99052?

Upgrade to a fixed version.

## Is CVE-2026-99052 being exploited?

There is no known exploitation of CVE-2026-99052 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-99052 and fix it if it is affected.

What it is: CVE-2026-99052 is a vulnerability in Linux, published on 23 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-99052 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-2026-99052/ (Markdown: https://insights.sbomify.com/CVE-2026-99052/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-99052
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-99052
- OSV: https://osv.dev/vulnerability/CVE-2026-99052

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-99052/
Summaries are generated and may contain mistakes; the official description above is the record.