CVE-2026-98866

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-98866", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.377Z", "datePublished": "2026-10-18T15:51:27.883Z", "dateUpdated": "2026-10-19T09:27:00.570Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:27:00.570Z"}, "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()."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/exec.c", "include/linux/sched.h", "kernel/exit.c", "kernel/fork.c", "kernel/sched/fair.c"], "versions": [{"version": "df0d98475954d655571979aa061ecb07d7e00392", "lessThan": "9436130e6da72af63289a4acb3aa0c1df07a3928", "status": "affected", "versionType": "git"}, {"version": "df0d98475954d655571979aa061ecb07d7e00392", "lessThan": "b636fef85bda7d1bab9c0a45067ab1508d79d946", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/exec.c", "include/linux/sched.h", "kernel/exit.c", "kernel/fork.c", "kernel/sched/fair.c"], "versions": [{"version": "7.2", "status": "affected"}, {"version": "0", "lessThan": "7.2", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.10", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.2", "versionEndExcluding": "7.2.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.2", "versionEndExcluding": "7.3"}]}]}], "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"}}}}

{}

{"affected": [{"affectedData": [{"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"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "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()."}], "id": "CVE-2026-98866", "lastModified": "2026-10-19T10:19:50.657", "metrics": {}, "published": "2026-10-18T16:17:41.117", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9436130e6da72af63289a4acb3aa0c1df07a3928"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b636fef85bda7d1bab9c0a45067ab1508d79d946"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: sched/cache: Introduce task_struct->sched_cache_grp to fix UAF", "id": "2555204", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2555204"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.7", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nsched/cache: Introduce task_struct->sched_cache_grp to fix UAF\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.\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:\nhttps://lore.kernel.org/lkml/apPb-Dr4nPYuHQOK@v4bel/\nConvert all scheduler code in fair.c and exit.c to use\np->sched_cache_grp instead of p->mm->sched_cache_grp.\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().", "A flaw was found in the Linux kernel. A use-after-free vulnerability, where memory is accessed after being released, occurs in the process scheduler cache component during task memory switches. A local user could exploit this flaw to cause a Denial of Service (DoS) through a system crash."], "name": "CVE-2026-98866", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-10-18T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-98866\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-98866\nhttps://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98866.mbox"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[df0d98475954d655571979aa061ecb07d7e00392,9436130e6da72af63289a4acb3aa0c1df07a3928)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[df0d98475954d655571979aa061ecb07d7e00392,b636fef85bda7d1bab9c0a45067ab1508d79d946)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "7.2"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,7.2)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.10,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3,*)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-10-18T21:00:10.632781+00:00", "updated": "2026-10-24T15:45:07.124991+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}