libfuse up to 3.18.1 FUSE File Parser fuse_uring_start use after free

CVSS Meta Temp Score
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CTI Interest Score
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7.6$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in libfuse up to 3.18.1. This affects the function fuse_uring_start of the component FUSE File Parser. This manipulation causes use after free. The identification of this vulnerability is CVE-2026-33150. The attack can only be executed locally. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability has been found in libfuse up to 3.18.1 and classified as critical. Affected by this vulnerability is the function fuse_uring_start of the component FUSE File Parser. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

libfuse is the reference implementation of the Linux FUSE. From version 3.18.0 to before version 3.18.2, a use-after-free vulnerability in the io_uring subsystem of libfuse allows a local attacker to crash FUSE filesystem processes and potentially execute arbitrary code. When io_uring thread creation fails due to resource exhaustion (e.g., cgroup pids.max), fuse_uring_start() frees the ring pool structure but stores the dangling pointer in the session state, leading to a use-after-free when the session shuts down. The trigger is reliable in containerized environments where cgroup pids.max limits naturally constrain thread creation. This issue has been patched in version 3.18.2.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-33150 since 03/17/2026. The exploitation appears to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 303272 (Linux Distros Unpatched Vulnerability : CVE-2026-33150), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.18.2 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 49fcd891a58f622c098e2ca67d66086f7b213836 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (303272), EUVD (EUVD-2026-13786) and CERT Bund (WID-SEC-2026-0913). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • Red Hat FUSE

Productinfo

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Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.8
VulDB Meta Temp Score: 7.6

VulDB Base Score: 7.8
VulDB Temp Score: 7.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.8
CNA Vector (GitHub_M): 🔒

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 303272
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-33150

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: libfuse 3.18.2
Patch: 49fcd891a58f622c098e2ca67d66086f7b213836

Timelineinfo

03/17/2026 CVE reserved
03/20/2026 +3 days Advisory disclosed
03/20/2026 +0 days VulDB entry created
03/30/2026 +10 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-qxv7-xrc2-qmfx
Status: Confirmed

CVE: CVE-2026-33150 (🔒)
GCVE (CVE): GCVE-0-2026-33150
GCVE (VulDB): GCVE-100-352129
EUVD: 🔒
CERT Bund: WID-SEC-2026-0913 - Red Hat FUSE (libfuse): Mehrere Schwachstellen ermöglichen Codeausführung und DoS

Entryinfo

Created: 03/20/2026 23:30
Updated: 03/30/2026 14:27
Changes: 03/20/2026 23:30 (68), 03/21/2026 03:55 (1), 03/22/2026 06:39 (2), 03/27/2026 01:04 (1), 03/30/2026 14:27 (7)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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