CVE-2026-90140

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

cuse: wait for pending RCU callbacks on module exit

Since commit 053fc4f755ad ("fuse: fix UAF in rcu pathwalks"),

fuse_conn_put() frees the fuse_conn through call_rcu() rather than

synchronously. For cuse, fc->release is cuse_fc_release(), which

lives in the cuse module. If the module is removed before the RCU

grace period ends, the callback jumps into freed module memory:

userspace / module unload | RCU softirq

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

close(/dev/cuse) |

cuse_channel_release() |

fuse_dev_release() |

fuse_conn_put(fch->conn) |

call_rcu(delayed_release) ------+---> callback queued

|

rmmod cuse |

cuse_exit() |

cuse_channel_destroy() |

... |

return

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References