{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "b44133ff03be30b55f23036e62f403a3f7784fce"
            },
            {
              "fixed": "0f0b6232af56441d0a2dcb173cc4f8d8aab39014"
            },
            {
              "fixed": "09301f1fdf2aef8cce34d0c4650c30e7edb1ced9"
            },
            {
              "fixed": "f1b4df9c260c51726da2e86e19322825fddeefd0"
            },
            {
              "fixed": "57077eeb586c42f124bc09e018449362223067b3"
            },
            {
              "fixed": "6f5fb689fdf80bdd143f22a502f9eb1f3c85e286"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.1.0"
            },
            {
              "fixed": "6.1.178"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.12.97"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.40"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64539.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: eir: Fix stack OOB write when prepending the Flags AD\n\neir_create_adv_data() builds the advertising data into a fixed-size\nbuffer (\"size\", 31 for the legacy path). It may prepend a 3-byte \"Flags\"\nAD structure (LE_AD_NO_BREDR on an LE-only controller) and then copies\nthe per-instance data without checking that it still fits:\n\n\tmemcpy(ptr, adv-\u003eadv_data, adv-\u003eadv_data_len);\n\ntlv_data_max_len() only reserves those 3 bytes when the user-supplied\nflags carry a managed-flags bit, so an instance added with flags == 0 is\naccepted with adv_data_len up to the full buffer. At advertise time the\nflags are still prepended, and the memcpy() writes 3 + adv_data_len\nbytes into the size-byte buffer:\n\n  BUG: KASAN: stack-out-of-bounds in eir_create_adv_data (net/bluetooth/eir.c:301)\n  Write of size 31 at addr ffff88800a547bdc by task kworker/u9:0/65\n  Workqueue: hci0 hci_cmd_sync_work\n   __asan_memcpy (mm/kasan/shadow.c:106)\n   eir_create_adv_data (net/bluetooth/eir.c:301)\n   hci_update_adv_data_sync (net/bluetooth/hci_sync.c:1310)\n   hci_schedule_adv_instance_sync (net/bluetooth/hci_sync.c:1817)\n   hci_cmd_sync_work (net/bluetooth/hci_sync.c:332)\n  This frame has 1 object:\n   [32, 64) 'cp'\n\nThe \"Flags\" structure is added by the kernel, not requested by\nuserspace, so only prepend it when it fits together with the instance\nadvertising data; when there is no room for both, drop the flags rather\nthan the user-provided data.\n\nReachable by a local user with CAP_NET_ADMIN owning an LE-only\ncontroller on the legacy advertising path.",
  "id": "CVE-2026-64539",
  "modified": "2026-07-29T03:30:36.817653426Z",
  "published": "2026-07-27T20:10:33.363Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/09301f1fdf2aef8cce34d0c4650c30e7edb1ced9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0f0b6232af56441d0a2dcb173cc4f8d8aab39014"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/57077eeb586c42f124bc09e018449362223067b3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6f5fb689fdf80bdd143f22a502f9eb1f3c85e286"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f1b4df9c260c51726da2e86e19322825fddeefd0"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64539.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64539"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.8.0",
  "summary": "Bluetooth: eir: Fix stack OOB write when prepending the Flags AD"
}