What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-20 · updated 2026-06-17
• Weakness: CWE-476

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.

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/7beb86c09b6ec5aab14dc25256ed8a5ad18554d7
• https://github.com/libfuse/libfuse/releases/tag/fuse-3.18.2
• https://github.com/libfuse/libfuse/security/advisories/GHSA-x669-v3mq-r358

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