{"id":"CVE-2026-90149","title":"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 ses…","summary":"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 ses…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","vendor":"Linux","product":"Linux","affected":["Linux >= a7878ca140084ec267ede48fce64d7e60f6d873e < 163c16e01f53fc8eb8d0f3484ae6c382265ecbbd","Linux >= a7878ca140084ec267ede48fce64d7e60f6d873e < 436a214514e24103159aea455147d58b44a8a585","Linux >= a7878ca140084ec267ede48fce64d7e60f6d873e < 2b03ebbf8d5e8f6af4ecd6c65375232dd1ec32cc","Linux 4.12"],"published":"2026-09-17","updated":"2026-09-18","sourceUpdated":"2026-09-18T18:17:44.120","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-90149","references":[{"url":"https://git.kernel.org/stable/c/163c16e01f53fc8eb8d0f3484ae6c382265ecbbd","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2b03ebbf8d5e8f6af4ecd6c65375232dd1ec32cc","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/436a214514e24103159aea455147d58b44a8a585","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"epss":0.00576,"epssPercentile":0.45958,"ingestedAt":"2026-09-17T16:21:47.877Z","slug":"CVE-2026-90149","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":207149,"id":"CVE-2026-90149","ts":1789757336132,"field":"cvss","old":null,"new":"7.5"},{"seq":207148,"id":"CVE-2026-90149","ts":1789757336132,"field":"severity","old":"none","new":"high"}]}