{"id":"AZL-83318","summary":"CVE-2026-31500 affecting package kernel for versions less than 6.6.134.1-2","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: btintel: serialize btintel_hw_error() with hci_req_sync_lock\n\nbtintel_hw_error() issues two __hci_cmd_sync() calls (HCI_OP_RESET\nand Intel exception-info retrieval) without holding\nhci_req_sync_lock().  This lets it race against\nhci_dev_do_close() -\u003e btintel_shutdown_combined(), which also runs\n__hci_cmd_sync() under the same lock.  When both paths manipulate\nhdev-\u003ereq_status/req_rsp concurrently, the close path may free the\nresponse skb first, and the still-running hw_error path hits a\nslab-use-after-free in kfree_skb().\n\nWrap the whole recovery sequence in hci_req_sync_lock/unlock so it\nis serialized with every other synchronous HCI command issuer.\n\nBelow is the data race report and the kasan report:\n\n  BUG: data-race in __hci_cmd_sync_sk / btintel_shutdown_combined\n\n  read of hdev-\u003ereq_rsp at net/bluetooth/hci_sync.c:199\n  by task kworker/u17:1/83:\n   __hci_cmd_sync_sk+0x12f2/0x1c30 net/bluetooth/hci_sync.c:200\n   __hci_cmd_sync+0x55/0x80 net/bluetooth/hci_sync.c:223\n   btintel_hw_error+0x114/0x670 drivers/bluetooth/btintel.c:254\n   hci_error_reset+0x348/0xa30 net/bluetooth/hci_core.c:1030\n\n  write/free by task ioctl/22580:\n   btintel_shutdown_combined+0xd0/0x360\n    drivers/bluetooth/btintel.c:3648\n   hci_dev_close_sync+0x9ae/0x2c10 net/bluetooth/hci_sync.c:5246\n   hci_dev_do_close+0x232/0x460 net/bluetooth/hci_core.c:526\n\n  BUG: KASAN: slab-use-after-free in\n   sk_skb_reason_drop+0x43/0x380 net/core/skbuff.c:1202\n  Read of size 4 at addr ffff888144a738dc\n  by task kworker/u17:1/83:\n   __hci_cmd_sync_sk+0x12f2/0x1c30 net/bluetooth/hci_sync.c:200\n   __hci_cmd_sync+0x55/0x80 net/bluetooth/hci_sync.c:223\n   btintel_hw_error+0x186/0x670 drivers/bluetooth/btintel.c:260","modified":"2026-08-28T17:47:56.711494892Z","published":"2026-04-22T14:16:48Z","upstream":["CVE-2026-31500"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31500"}],"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-83318.json"}}],"schema_version":"1.9.0"}