Bluetooth Classic HFP AG wipes an object still linked in the SDP request list on connect failure, causing a NULL dereference

{
  "id": "fec4facf1fbb5dc12c145da6014606caaca63c26f8cfb581f87db14dab8a2367",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-82389",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Bluetooth Classic HFP AG wipes an object still linked in the SDP request list on connect failure, causing a NULL dereference",
    "summary": "In the Bluetooth Classic Hands-Free Profile Audio Gateway role, hfp_ag_create() in subsys/bluetooth/host/classic/hfp_ag.c starts an SDP discovery toward the peer, which links the embedded ag->sdp_param._node into the SDP client's pending request list in subsys/bluetooth/host/classic/sdp.c. If the subsequent bt_rfcomm_dlc_connect() call fails, bt_hfp_ag_connect() cleaned up by memset()-ing the entire AG object while that node was still linked, and while ag->slc_work could still be queued on the system work queue. An in-flight SDP discovery cannot be cancelled — bt_sdp_discover_cancel() is declared in the public header but has no implementation — so the request stays in the list with its func, pool and uuid pointers zeroed. The RFCOMM channel passed to bt_hfp_ag_connect() is taken from the peer's own SDP Hands-Free service record in the normal AG flow (bt_sdp_get_proto_param() performs no range validation, and samples/bluetooth/classic/handsfree_ag feeds the value straight through), so a remote BR/EDR device in radio range that advertises an RFCOMM channel outside the valid range 0x01..0x1e deterministically forces bt_rfcomm_dlc_connect() to fail and reach the wipe. Reading the peer's SDP record requires no pairing, and the peer can also trigger the failure by dropping the ACL or racing an RFCOMM DLC on the same DLCI at the right moment. When the SDP client next advances its request list, sdp_client_discover() dereferences the zeroed parameters — net_buf_alloc(param->pool, …) w",
    "evidence": "cve:CVE-2026-82389",
    "products": [
      {
        "name": {
          "value": "zephyr",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-82389",
      "aliases": [
        "CVE-2026-82389"
      ],
      "metrics": [
        {
          "format": "CVSS",
          "cvssV3_1": {
            "version": "3.1",
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
          }
        }
      ],
      "affected": [
        {
          "vendor": "zephyrproject",
          "product": "zephyr",
          "versions": [
            {
              "status": "affected",
              "version": "4.4.0",
              "lessThan": "4.5.0",
              "versionType": "semver"
            }
          ],
          "packageName": "zephyr",
          "programFiles": [
            "subsys/bluetooth/host/classic/hfp_ag.c",
            "subsys/bluetooth/host/classic/hfp_ag_internal.h"
          ],
          "collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
          "defaultStatus": "unaffected",
          "programRoutines": [
            {
              "name": "bt_hfp_ag_connect"
            },
            {
              "name": "bt_hfp_ag_discover_cb"
            }
          ]
        }
      ],
      "modified": "2026-10-26T17:37:10.685Z",
      "provider": "cve",
      "references": [
        "https://github.com/zephyrproject-rtos/zephyr/commit/18a3243b21ef6298988a3034dbda2704a7ad73a4",
        "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-rrqj-542q-26jm"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-82389",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-10-26T16:49:22.774483Z"
                  }
                }
              }
            ],
            "providerMetadata": {
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP",
              "dateUpdated": "2026-10-26T17:37:10.685Z"
            }
          }
        ],
        "cna": {
          "orgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
          "shortName": "zephyr",
          "dateUpdated": "2026-10-26T16:08:53.604Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-82389",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 326395,
  "published_at": "2026-10-26T16:08:53.604+00:00"
}