{"id":"CVE-2026-90149","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-90149","summary":"NFSv4/flexfiles: fix NULL dereference for NFSv4.0 data servers","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nNFSv4/flexfiles: fix NULL dereference for NFSv4.0 data servers\n\nflexfiles accepts NFSv4.0 data servers, but two NFSv4 code paths assume\nthe data server client has a session. Unlike NFSv4.1+, an NFSv4.0 client\nhas no session (clp->cl_session is NULL; it uses clp->cl_slot_tbl), so\nI/O to a v4.0 flexfiles DS oopses:\n\n  - nfs4_init_ds_session() dereferences clp->cl_session->session_state\n    while seeding the DS lease. It also only seeds cl_lease_time when\n    NFS4_SESSION_INITING is set; without a session that never happens, so\n    cl_lease_time stays 0 and nfs4_renew_state() busy-loops, requeuing\n    every 5 seconds. Seed the lease whenever there is no session and\n    return before touching session state.\n\n  - ff_layout_async_handle_error_v4() dereferences\n    clp->cl_session->fc_slot_table on every DS I/O error. Fall back to the\n    v4.0 transport slot table (clp->cl_slot_tbl) when there is no session.","published":"2026-09-17T16:06:43.671Z","modified":"2026-09-19T03:47:24.841243248Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.18.52"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/163c16e01f53fc8eb8d0f3484ae6c382265ecbbd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2b03ebbf8d5e8f6af4ecd6c65375232dd1ec32cc"},{"type":"WEB","url":"https://git.kernel.org/stable/c/436a214514e24103159aea455147d58b44a8a585"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90149.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90149"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-19T03:47:24.841243248Z"}}