{"id":"CVE-2026-98866","revision":"da103763bdda4a548bb7c55b69552a9f","records":[{"revision":"da103763bdda4a548bb7c55b69552a9f","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-98866","aliases":[],"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":0,"publishedAt":"2026-10-18T15:51:27.883+00:00","modifiedAt":"2026-10-19T09:27:00.57+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/exec.c\",\n                        \"include/linux/sched.h\",\n                        \"kernel/exit.c\",\n                        \"kernel/fork.c\",\n                        \"kernel/sched/fair.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"df0d98475954d655571979aa061ecb07d7e00392\",\n                            \"lessThan\": \"9436130e6da72af63289a4acb3aa0c1df07a3928\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"df0d98475954d655571979aa061ecb07d7e00392\",\n                            \"lessThan\": \"b636fef85bda7d1bab9c0a45067ab1508d79d946\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"fs/exec.c\",\n                        \"include/linux/sched.h\",\n                        \"kernel/exit.c\",\n                        \"kernel/fork.c\",\n                        \"kernel/sched/fair.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"7.2\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"7.2\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.10\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/9436130e6da72af63289a4acb3aa0c1df07a3928","https://git.kernel.org/stable/c/b636fef85bda7d1bab9c0a45067ab1508d79d946"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98866","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-98866","identifiers":["CVE-2026-98866"]},"retained":false,"historicalAffected":[]}],"coverage":[]}