{"id":"CVE-2026-90140","published":"2026-09-17T17:17:06.710","lastModified":"2026-09-17T17:17:06.710","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncuse: wait for pending RCU callbacks on module exit\n\nSince commit 053fc4f755ad (\"fuse: fix UAF in rcu pathwalks\"),\nfuse_conn_put() frees the fuse_conn through call_rcu() rather than\nsynchronously.  For cuse, fc->release is cuse_fc_release(), which\nlives in the cuse module.  If the module is removed before the RCU\ngrace period ends, the callback jumps into freed module memory:\n\n      userspace / module unload      |        RCU softirq\n~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n close(/dev/cuse)                    |\n  cuse_channel_release()             |\n   fuse_dev_release()                |\n    fuse_conn_put(fch->conn)         |\n     call_rcu(delayed_release) ------+---> callback queued\n                                     |\n rmmod cuse                          |\n  cuse_exit()                        |\n   cuse_channel_destroy()            |\n   ...                               |\n   return                            |\n                                     |\n <module text freed>                 |\n                                     |  rcu_do_batch()\n                                     |   delayed_release()\n                                     |    fc->release()\n                                     |     -> cuse_fc_release()\n                                     |        ^^^ freed text!\n\nThe freed module text is unmapped by vfree(), so the jump into the\nstale callback triggers a page-fault Oops.  If the virtual address\nis subsequently reused, the callback could execute unrelated code\n(undefined behaviour).\n\nFix this by calling rcu_barrier() in cuse_exit() so that any pending\nfuse_conn release callback completes before the module is removed.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/389bd349ddbcf90dbd8a4f2a4ab6e552d53df134","tags":[]},{"url":"https://git.kernel.org/stable/c/45ae914b2f6ea56fc2f1c017fdee4e995bcb4c0e","tags":[]},{"url":"https://git.kernel.org/stable/c/4deb3edead0c0e172cc7349e8855d741d3c5e162","tags":[]},{"url":"https://git.kernel.org/stable/c/7fe415e1cd8fa875be263670c0ab47109818abb6","tags":[]},{"url":"https://git.kernel.org/stable/c/a1b46aee33d83f14ed62d7fdef1a91d3e0b732a9","tags":[]},{"url":"https://git.kernel.org/stable/c/ac5c499413385cea3e0220d6050408d50842891d","tags":[]},{"url":"https://git.kernel.org/stable/c/c40f3f24839f8404325a2099e26c2a04786ae309","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}