{"id":"CVE-2026-98219","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Close the pre-enable ops error claim window\n\nscx_alloc_and_add_sched() publishes ops->priv before\nscx_root_enable_workfn() switches the state to SCX_ENABLING…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Close the pre-enable ops error claim window\n\nscx_alloc_and_add_sched() publishes ops->priv before\nscx_root_enable_workfn() switches the state to SCX_ENABLING…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 105dcd005be2ac1d5541921db8feb1d0f98d59d5 < 959c66dc4a915be306c35691095c787c61dc7df9","Linux >= 105dcd005be2ac1d5541921db8feb1d0f98d59d5 < c7a1c6e8004ab12a9c9bfdcb603f60f9bf4a3cee","Linux 7.1"],"published":"2026-10-06","updated":"2026-10-06","sourceUpdated":"2026-10-06T09:18:08.730","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98219","references":[{"url":"https://git.kernel.org/stable/c/959c66dc4a915be306c35691095c787c61dc7df9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c7a1c6e8004ab12a9c9bfdcb603f60f9bf4a3cee","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-10-06T08:50:17.439Z","slug":"CVE-2026-98219","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Close the pre-enable ops error claim window\n\nscx_alloc_and_add_sched() publishes ops->priv before\nscx_root_enable_workfn() switches the state to SCX_ENABLING. An error\nclaimed via scx_bpf_error_bstr() from an associated BPF program in that\nwindow is consumed by scx_disable_workfn(), which takes the pre-enable\nshortcut in scx_root_disable(). The shortcut returns without any teardown\nand restores SCX_DISABLED with an unconditional scx_set_enable_state() xchg\nracing the enable workfn's own transition. The enable then completes with\nthe claim consumed: the scheduler stays up but can never be disabled again,\nand bpf_scx_unreg() frees it while still in use, resulting in a\nuse-after-free. Both WARN_ON_ONCE()s fire back to back:\n\n  WARNING: kernel/sched/ext/ext.c:7522 at\n  scx_root_enable_workfn+0xeec/0x1be0, CPU#3: scx_enable_help/276\n\n  WARNING: kernel/sched/ext/ext.c:6398 at scx_root_disable+0xb50/0xdb8,\n  CPU#0: sched_ext_helpe/664\n\nscx_root_enable_workfn() switches to SCX_ENABLING before the scheduler\nallocation, so ops->priv is never visible while SCX_DISABLED. The allocation\nfailure path restores SCX_DISABLED.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}