{"cve":"CVE-2026-90326","nvd":{"published":"2026-09-17T17:17:30.673","modified":"2026-10-21T13:20:50.293","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nblk-cgroup: fix race between policy activation and blkg destruction\n\nWhen switching an IO scheduler on a block device, blkcg_activate_policy()\nallocates blkg_policy_data (pd) for all blkgs attached to the queue.\nHowever, blkcg_activate_policy() may race with concurrent blkcg deletion,\nleading to use-after-free and memory leak issues.\n\nThe use-after-free occurs in the following race:\n\nT1 (blkcg_activate_policy):\n  - Successfully allocates pd for blkg1 (loop0->queue, blkcgA)\n  - Fails to allocate pd for blkg2 (loop0->queue, blkcgB)\n  - Enters the enomem rollback path to release blkg1 resources\n\nT2 (blkcg deletion):\n  - blkcgA is deleted concurrently\n  - blkg1 is freed via blkg_free_workfn()\n  - blkg1->pd is freed\n\nT1 (continued):\n  - Rollback path accesses blkg1->pd->online after pd is freed\n  - Triggers use-after-free\n\nIn addition, blkg_free_workfn() frees pd before removing the blkg from\nq->blkg_list. This allows blkcg_activate_policy() to allocate a new pd\nfor a blkg that is being destroyed, leaving the newly allocated pd\nunreachable when the blkg is finally freed.\n\nFix these races by extending blkcg_mutex coverage to serialize\nblkcg_activate_policy() rollback and blkg destruction, ensuring pd\nlifecycle is synchronized with blkg list visibility.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/083b58373463a6e5ee60ecb135269348f68ad7df","https://git.kernel.org/stable/c/17c18a0df70c2b89ff7fcd74622f1540e98d00fd","https://git.kernel.org/stable/c/2cf9f50a38c1839e549a08e22aa35e8d69e2c8fd","https://git.kernel.org/stable/c/5313d4d41739b0cb63000747c97bb1217ac45f3e","https://git.kernel.org/stable/c/91062e3a9ed251726df4e20ff9a1113f1c8ded59"],"products":[],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-90326","score":0.00171,"percentile":0.0644,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}