{"id":"CVE-2026-90206","summary":"nvmet: fix max_qid race between configfs and controller allocation","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnvmet: fix max_qid race between configfs and controller allocation\n\nThe function nvmet_subsys_attr_qid_max_store() can race against\nnvmet_alloc_ctrl() when a subsystem's max_qid limit is modified.\n\nSuppose max_qid is currently 64. If nvmet_alloc_ctrl() executes:\nctrl-\u003esqs = kzalloc_objs(struct nvmet_sq *, subsys-\u003emax_qid + 1);\nand at this exact point, a userspace process changes max_qid to 128,\nnvmet_subsys_attr_qid_max_store() will set the new max_qid value. It\nattempts to delete active controllers to force a reconnect, but the\nnew controller won't be deleted because it hasn't been added to the\nsubsys-\u003ectrls list yet.\n\nnvmet_alloc_ctrl() then proceeds and adds the new controller to the\nsubsys-\u003ectrls list. Later, when nvmet_install_queue() is called, it\nwill see max_qid set to 128, but the memory allocated for sqs is only\nsized for 64 entries. This results in a KASAN out-of-bounds warning\nand potential memory corruptions.\n\nFix this by protecting the queue allocations and list insertion in\nnvmet_alloc_ctrl() with down_read(&nvmet_config_sem). Because\nnvmet_subsys_attr_qid_max_store() acquires down_write(&nvmet_config_sem)\nto modify the attribute, this safely prevents the configfs writer from\nmodifying max_qid during controller creation.\n\nCopy the max_qid from the subsystem to the controller's structure\nduring the allocation; ctrl-\u003emax_qid never changes as long as the\ncontroller remains in LIVE state, so this will prevent similar race\nconditions.","modified":"2026-09-19T03:47:25.055145302Z","published":"2026-09-17T16:07:22.173Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90206.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2c23fc91789dfd9db746edb3ae9b90d65fabd410"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f1a8846e06388113dfdbb89dee005083fa9afdf9"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90206.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90206"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3e980f5995e0bb4d86fef873a9c9ad66721580d0"},{"fixed":"2c23fc91789dfd9db746edb3ae9b90d65fabd410"},{"fixed":"f1a8846e06388113dfdbb89dee005083fa9afdf9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90206.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.1.0"},{"fixed":"7.2.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90206.json"}}],"schema_version":"1.9.0"}