{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "df0d98475954d655571979aa061ecb07d7e00392"
            },
            {
              "fixed": "9436130e6da72af63289a4acb3aa0c1df07a3928"
            },
            {
              "fixed": "b636fef85bda7d1bab9c0a45067ab1508d79d946"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.2.0"
            },
            {
              "fixed": "7.2.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98866.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched/cache: Introduce task_struct-\u003esched_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-\u003esched_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-\u003esched_cache_grp instead of p-\u003emm-\u003esched_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().",
  "id": "CVE-2026-98866",
  "modified": "2026-10-19T02:30:39.793948869Z",
  "published": "2026-10-18T15:51:27.883Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9436130e6da72af63289a4acb3aa0c1df07a3928"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b636fef85bda7d1bab9c0a45067ab1508d79d946"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98866.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98866"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "sched/cache: Introduce task_struct-\u003esched_cache_grp to fix UAF"
}