{"id":"CVE-2026-90095","summary":"fuse: Fix the condition to enable over-io-uring","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nfuse: Fix the condition to enable over-io-uring\n\nThe existing condition in fuse_uring_cmd() is there only to avoid\ndisabling io-uring for connections that already run with it, missing\nwas a condition to refuse any IORING_OP_URING_CMD if the\nconnection/channel didn't get enabled because of missing FUSE_INIT\nreply flag FUSE_OVER_IO_URING. Without the reply flag the barrier in\nfuse_uring_ready() doesn't work and IO could already be going on and\ncause deadlock states (at a minimum one between fch-\u003ebg_lock and\nqueue-\u003elock).\n\nThe change itself is trivial, but brings behavior change,\nFUSE_OVER_IO_URING has to be set in the FUSE_INIT_REPLY by fuse servers\nto accept any IORING_OP_URING_CMD. Libfuse does that and the only\nnon-libfuse implementation I found (fractal-fuse) also does it.\nQemu patches for fuse-io-uring are not merged yet, as far as I know.\n\nMoved up is the smp_load_acquire(&fch-\u003einitialized) check, as a\nfuse-server implementation might try to setup io-uring before FUSE_INIT\nis processed and might have gotten -EOPNOTSUPP instead of -EAGAIN.\n\nAlso fixed is a stale comment that explains the handling of the\nFUSE_OVER_IO_URING flag in early RFC versions.\n\nIf there should be a report from any library or application we\nprobably need to revert this commit.","modified":"2026-09-18T03:48:35.481936191Z","published":"2026-09-17T16:06:08.197Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90095.json","cna_assigner":"Linux"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1f59015e958174e89be58cc8db16d70a60d17255"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8f9a725d89711ad027f6b7183586ef91528f106d"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90095.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90095"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3393ff964e0fa5def66570c54a4612bf9df06b76"},{"fixed":"8f9a725d89711ad027f6b7183586ef91528f106d"},{"fixed":"1f59015e958174e89be58cc8db16d70a60d17255"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90095.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.14.0"},{"fixed":"7.2.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-90095.json"}}],"schema_version":"1.9.0"}