{"api_version":"1","generated_at":"2026-10-21T19:30:15+00:00","cve":"CVE-2026-98866","urls":{"html":"https://cve.report/CVE-2026-98866","api":"https://cve.report/api/cve/CVE-2026-98866.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98866","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98866"},"summary":{"title":"sched/cache: Introduce task_struct->sched_cache_grp to fix UAF","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/cache: Introduce task_struct->sched_cache_grp to fix UAF\n\nAdd a sched_cache_grp pointer to task_struct so that scheduler code\ncan access the cache group directly via the task, without going\nthrough mm->sched_cache_grp.  This decouples the scheduler's hot-path\naccesses from the mm_struct.\n\nEach task holds its own refcount on the sched_cache_group, separate\nfrom the reference held by its mm_struct.  The reference is acquired\nin copy_mm() (fork) and exec_mmap() (exec), and released in exit_mm().\nThis fixes the use-after-free when account_mm_sched() reaches the group\nthrough a task whose mm is being switched, as reported by Hyunwoo:\n\n  https://lore.kernel.org/lkml/apPb-Dr4nPYuHQOK@v4bel/\n\nConvert all scheduler code in fair.c and exit.c to use\np->sched_cache_grp instead of p->mm->sched_cache_grp.\n\nKeep the fork/exec/exit reference management out of the generic mm\npaths: add sched_cache_fork(), sched_cache_fork_cleanup(),\nsched_cache_exec_mmap() and sched_cache_exit_mm() in\nkernel/sched/cache_sched.c (with empty stubs for !CONFIG_SCHED_CACHE),\nso fs/exec.c, kernel/fork.c and kernel/exit.c each call one helper\ninstead of open-coding the refcounting under #ifdef.  Also add\nsched_cache_group_get() and task_cache_group_get().","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-18 16:17:41","updated_at":"2026-10-19 10:19:50"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/b636fef85bda7d1bab9c0a45067ab1508d79d946","name":"https://git.kernel.org/stable/c/b636fef85bda7d1bab9c0a45067ab1508d79d946","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9436130e6da72af63289a4acb3aa0c1df07a3928","name":"https://git.kernel.org/stable/c/9436130e6da72af63289a4acb3aa0c1df07a3928","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98866","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98866","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected df0d98475954d655571979aa061ecb07d7e00392 9436130e6da72af63289a4acb3aa0c1df07a3928 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected df0d98475954d655571979aa061ecb07d7e00392 b636fef85bda7d1bab9c0a45067ab1508d79d946 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.2","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.10 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/exec.c","include/linux/sched.h","kernel/exit.c","kernel/fork.c","kernel/sched/fair.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"9436130e6da72af63289a4acb3aa0c1df07a3928","status":"affected","version":"df0d98475954d655571979aa061ecb07d7e00392","versionType":"git"},{"lessThan":"b636fef85bda7d1bab9c0a45067ab1508d79d946","status":"affected","version":"df0d98475954d655571979aa061ecb07d7e00392","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/exec.c","include/linux/sched.h","kernel/exit.c","kernel/fork.c","kernel/sched/fair.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"7.2"},{"lessThan":"7.2","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.10","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.10","versionStartIncluding":"7.2","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"7.2","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/cache: Introduce task_struct->sched_cache_grp to fix UAF\n\nAdd a sched_cache_grp pointer to task_struct so that scheduler code\ncan access the cache group directly via the task, without going\nthrough mm->sched_cache_grp.  This decouples the scheduler's hot-path\naccesses from the mm_struct.\n\nEach task holds its own refcount on the sched_cache_group, separate\nfrom the reference held by its mm_struct.  The reference is acquired\nin copy_mm() (fork) and exec_mmap() (exec), and released in exit_mm().\nThis fixes the use-after-free when account_mm_sched() reaches the group\nthrough a task whose mm is being switched, as reported by Hyunwoo:\n\n  https://lore.kernel.org/lkml/apPb-Dr4nPYuHQOK@v4bel/\n\nConvert all scheduler code in fair.c and exit.c to use\np->sched_cache_grp instead of p->mm->sched_cache_grp.\n\nKeep the fork/exec/exit reference management out of the generic mm\npaths: add sched_cache_fork(), sched_cache_fork_cleanup(),\nsched_cache_exec_mmap() and sched_cache_exit_mm() in\nkernel/sched/cache_sched.c (with empty stubs for !CONFIG_SCHED_CACHE),\nso fs/exec.c, kernel/fork.c and kernel/exit.c each call one helper\ninstead of open-coding the refcounting under #ifdef.  Also add\nsched_cache_group_get() and task_cache_group_get()."}],"providerMetadata":{"dateUpdated":"2026-10-19T09:27:00.570Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/9436130e6da72af63289a4acb3aa0c1df07a3928"},{"url":"https://git.kernel.org/stable/c/b636fef85bda7d1bab9c0a45067ab1508d79d946"}],"title":"sched/cache: Introduce task_struct->sched_cache_grp to fix UAF","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98866","datePublished":"2026-10-18T15:51:27.883Z","dateReserved":"2026-09-25T10:25:14.377Z","dateUpdated":"2026-10-19T09:27:00.570Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-18 16:17:41","lastModifiedDate":"2026-10-19 10:19:50","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98866","Ordinal":"1","Title":"sched/cache: Introduce task_struct->sched_cache_grp to fix UAF","CVE":"CVE-2026-98866","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98866","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/cache: Introduce task_struct->sched_cache_grp to fix UAF\n\nAdd a sched_cache_grp pointer to task_struct so that scheduler code\ncan access the cache group directly via the task, without going\nthrough mm->sched_cache_grp.  This decouples the scheduler's hot-path\naccesses from the mm_struct.\n\nEach task holds its own refcount on the sched_cache_group, separate\nfrom the reference held by its mm_struct.  The reference is acquired\nin copy_mm() (fork) and exec_mmap() (exec), and released in exit_mm().\nThis fixes the use-after-free when account_mm_sched() reaches the group\nthrough a task whose mm is being switched, as reported by Hyunwoo:\n\n  https://lore.kernel.org/lkml/apPb-Dr4nPYuHQOK@v4bel/\n\nConvert all scheduler code in fair.c and exit.c to use\np->sched_cache_grp instead of p->mm->sched_cache_grp.\n\nKeep the fork/exec/exit reference management out of the generic mm\npaths: add sched_cache_fork(), sched_cache_fork_cleanup(),\nsched_cache_exec_mmap() and sched_cache_exit_mm() in\nkernel/sched/cache_sched.c (with empty stubs for !CONFIG_SCHED_CACHE),\nso fs/exec.c, kernel/fork.c and kernel/exit.c each call one helper\ninstead of open-coding the refcounting under #ifdef.  Also add\nsched_cache_group_get() and task_cache_group_get().","Type":"Description","Title":"sched/cache: Introduce task_struct->sched_cache_grp to fix UAF"}]}}}