# CVE-2026-33179: libfuse: NULL Pointer Dereference and Memory Leak in io_uring Queue Initialization

> A local attacker can crash the FUSE daemon or exhaust resources via a NULL pointer dereference in the io_uring transport, requiring the io_uring feature to be enabled.

- **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:** 20 Mar 2026
- **Updated:** 25 Mar 2026
- **Also known as:** BELL-CVE-2026-33179, DEBIAN-CVE-2026-33179, GHSA-x669-v3mq-r358

## What is CVE-2026-33179?

CVE-2026-33179 is a medium-severity vulnerability in libfuse, published on 20 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

libfuse is the reference implementation of the Linux FUSE. From version 3.18.0 to before version 3.18.2, a NULL pointer dereference and memory leak in fuse_uring_init_queue allows a local user to crash the FUSE daemon or cause resource exhaustion. When numa_alloc_local fails during io_uring queue entry setup, the code proceeds with NULL pointers. When fuse_uring_register_queue fails, NUMA allocations are leaked and the function incorrectly returns success. Only the io_uring transport is affected; the traditional /dev/fuse path is not affected. PoC confirmed with AddressSanitizer/LeakSanitizer. This issue has been patched in version 3.18.2.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-33179?

It affects 1 product.


Products: Libfuse Project Libfuse.

## How do I fix CVE-2026-33179?

Upgrade to a fixed version.

## Is CVE-2026-33179 being exploited?

There is no known exploitation of CVE-2026-33179 in the wild and no public exploit code.

## Other vulnerabilities in libfuse

- [CVE-2026-33150](https://insights.sbomify.com/CVE-2026-33150/): Use After Free in libfuse (high 7.8)
- [CVE-2010-3879](https://insights.sbomify.com/CVE-2010-3879/): Path traversal in n/a (medium 5.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-33179 and fix it if it is affected.

What it is: CVE-2026-33179 is a medium-severity vulnerability in libfuse, published on 20 Mar 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-2026-33179 in the wild and no public exploit code.

Affected product: libfuse. 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-2026-33179/ (Markdown: https://insights.sbomify.com/CVE-2026-33179/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-33179
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33179
- OSV: https://osv.dev/vulnerability/CVE-2026-33179

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-33179/
Summaries are generated and may contain mistakes; the official description above is the record.