What’s Vulnerable › Vulnerabilities

CVE-2026-33150: Use After Free in libfuse

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-20 · updated 2026-07-15
• Weakness: CWE-416

Description

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.

Affected products

• libfuse: from 3.18.0 before 3.18.2 — fixed in 3.18.2

How to fix

Upgrade to a fixed version: libfuse 3.18.2. Check the vendor advisory for mitigations.

References

• https://github.com/libfuse/libfuse/commit/49fcd891a58f622c098e2ca67d66086f7b213836
• https://github.com/libfuse/libfuse/releases/tag/fuse-3.18.2
• https://github.com/libfuse/libfuse/security/advisories/GHSA-qxv7-xrc2-qmfx
• https://access.redhat.com/security/cve/CVE-2026-33150
• https://bugzilla.redhat.com/show_bug.cgi?id=2449771
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33150.json

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