# CVE-2026-53311: fuse: fix uninit-value in fuse_dentry_revalidate()

> An uninitialized value in the Linux kernel FUSE filesystem can lead to a crash or undefined behavior during file operations.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** 26 Jun 2026
- **Updated:** 26 Jun 2026
- **Also known as:** BELL-CVE-2026-53311, DEBIAN-CVE-2026-53311, GHSA-32q2-cq6r-mpm8, UBUNTU-CVE-2026-53311

## What is CVE-2026-53311?

CVE-2026-53311 is a medium-severity vulnerability in Linux kernel, published on 26 Jun 2026. 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:

fuse: fix uninit-value in fuse_dentry_revalidate()

fuse_dentry_revalidate() may be called with a dentry that didn't had
->d_time initialised.  The issue was found with KMSAN, where lookup_open()
calls __d_alloc(), followed by d_revalidate(), as shown below:

=====================================================
BUG: KMSAN: uninit-value in fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394
 fuse_dentry_revalidate+0x150/0x13d0 fs/fuse/dir.c:394
 d_revalidate fs/namei.c:1030 [inline]
 lookup_open fs/namei.c:4405 [inline]
 open_last_lookups fs/namei.c:4583 [inline]
 path_openat+0x1614/0x64c0 fs/namei.c:4827
 do_file_open+0x2aa/0x680 fs/namei.c:4859
[...]

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4466 [inline]
 slab_alloc_node mm/slub.c:4788 [inline]
 kmem_cache_alloc_lru_noprof+0x382/0x1280 mm/slub.c:4807
 __d_alloc+0x55/0xa00 fs/dcache.c:1740
 d_alloc_parallel+0x99/0x2740 fs/dcache.c:2604
 lookup_open fs/namei.c:4398 [inline]
 open_last_lookups fs/namei.c:4583 [inline]
 path_openat+0x135f/0x64c0 fs/namei.c:4827
 do_file_open+0x2aa/0x680 fs/namei.c:4859
[...]
=====================================================

Weakness: CWE-908 (Use of Uninitialized Resource)

## Which versions are affected by CVE-2026-53311?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53311?

Apply the vendor's patch.

## Is CVE-2026-53311 being exploited?

There is no known exploitation of CVE-2026-53311 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-2026-53311 and fix it if it is affected.

What it is: CVE-2026-53311 is a medium-severity vulnerability in Linux kernel, published on 26 Jun 2026. 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-2026-53311 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-2026-53311/ (Markdown: https://insights.sbomify.com/CVE-2026-53311/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53311
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53311
- OSV: https://osv.dev/vulnerability/CVE-2026-53311

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53311/
Summaries are generated and may contain mistakes; the official description above is the record.