{"id":"AZL-92721","summary":"CVE-2026-64036 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ncgroup/rstat: validate cpu before css_rstat_cpu() access\n\ncss_rstat_updated() is exposed as a BPF kfunc and accepts a\ncaller-provided cpu argument. The function uses cpu for per-cpu rstat\nlookups without checking whether it refers to a valid possible CPU.\n\nA BPF iter/cgroup program with CAP_BPF and CAP_PERFMON can pass an\ninvalid cpu value. On an unfixed UBSCAN_BOUNDS test kernel, cpu ==\n0x7fffffff triggers:\n\n  UBSAN: array-index-out-of-bounds in kernel/cgroup/rstat.c:31:9\n  index 2147483647 is out of range for type 'long unsigned int [64]'\n  Call Trace:\n    css_rstat_updated\n    bpf_iter_run_prog\n    cgroup_iter_seq_show\n    bpf_seq_read\n\nAdd cpu validation to the BPF-facing css_rstat_updated() kfunc and\nmove the common implementation to __css_rstat_updated() for in-kernel\ncallers.","modified":"2026-09-09T05:29:25Z","published":"2026-07-19T16:17:43Z","upstream":["CVE-2026-64036"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64036"}],"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-92721.json"}}],"schema_version":"1.9.0"}