SB20260425200 - Multiple vulnerabilities in libfuse

Description

This security bulletin contains information about 2 secuirty vulnerabilities.

1) NULL pointer dereference (CVE-ID: CVE-2026-33179)

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to null pointer dereference in fuse_uring_init_queue when initializing io_uring queue entries after NUMA allocation failure. A local user can trigger allocation failure conditions to cause a denial of service.

Only the io_uring transport is affected; the traditional /dev/fuse path is not affected.

2) Use-after-free (CVE-ID: CVE-2026-33150)

The vulnerability allows a local user to execute arbitrary code.

The vulnerability exists due to use-after-free in the io_uring subsystem of libfuse when io_uring thread creation fails and the session later shuts down. A local user can trigger resource exhaustion that causes thread creation to fail to execute arbitrary code.

The issue can also crash FUSE filesystem processes using the io_uring transport on session shutdown. The io_uring transport must be explicitly enabled, and the trigger is reliable in containerized environments where cgroup pids.max limits constrain thread creation.

Remediation

Install update from vendor's website.

References

• https://github.com/libfuse/libfuse/security/advisories/GHSA-x669-v3mq-r358
• https://github.com/libfuse/libfuse/security/advisories/GHSA-qxv7-xrc2-qmfx