{"id":"AZL-102567","summary":"CVE-2026-90140 affecting package kernel 6.6.150.1-1","details":"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-\u003erelease 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-\u003econn)         |\n     call_rcu(delayed_release) ------+---\u003e callback queued\n                                     |\n rmmod cuse                          |\n  cuse_exit()                        |\n   cuse_channel_destroy()            |\n   ...                               |\n   return                            |\n                                     |\n \u003cmodule text freed\u003e                 |\n                                     |  rcu_do_batch()\n                                     |   delayed_release()\n                                     |    fc-\u003erelease()\n                                     |     -\u003e 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.","modified":"2026-09-18T14:17:50.552474581Z","published":"2026-09-17T17:17:06Z","upstream":["CVE-2026-90140"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90140"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-102567.json"}}],"schema_version":"1.9.0"}