{"id":"AZL-102774","summary":"CVE-2026-90326 affecting package kernel 6.6.150.1-1","details":"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-\u003equeue, blkcgA)\n  - Fails to allocate pd for blkg2 (loop0-\u003equeue, 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-\u003epd is freed\n\nT1 (continued):\n  - Rollback path accesses blkg1-\u003epd-\u003eonline after pd is freed\n  - Triggers use-after-free\n\nIn addition, blkg_free_workfn() frees pd before removing the blkg from\nq-\u003eblkg_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.","modified":"2026-09-18T14:16:35.919481453Z","published":"2026-09-17T17:17:30Z","upstream":["CVE-2026-90326"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90326"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-102774.json"}}],"schema_version":"1.9.0"}