{"id":"AZL-83228","summary":"CVE-2026-31458 affecting package kernel for versions less than 6.6.134.1-2","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/sysfs: check contexts-\u003enr before accessing contexts_arr[0]\n\nMultiple sysfs command paths dereference contexts_arr[0] without first\nverifying that kdamond-\u003econtexts-\u003enr == 1.  A user can set nr_contexts to\n0 via sysfs while DAMON is running, causing NULL pointer dereferences.\n\nIn more detail, the issue can be triggered by privileged users like\nbelow.\n\nFirst, start DAMON and make contexts directory empty\n(kdamond-\u003econtexts-\u003enr == 0).\n\n    # damo start\n    # cd /sys/kernel/mm/damon/admin/kdamonds/0\n    # echo 0 \u003e contexts/nr_contexts\n\nThen, each of below commands will cause the NULL pointer dereference.\n\n    # echo update_schemes_stats \u003e state\n    # echo update_schemes_tried_regions \u003e state\n    # echo update_schemes_tried_bytes \u003e state\n    # echo update_schemes_effective_quotas \u003e state\n    # echo update_tuned_intervals \u003e state\n\nGuard all commands (except OFF) at the entry point of\ndamon_sysfs_handle_cmd().","modified":"2026-08-28T17:47:43.657897097Z","published":"2026-04-22T14:16:41Z","upstream":["CVE-2026-31458"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31458"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.134.1-2"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-83228.json"}}],"schema_version":"1.9.0"}