wifi: ath12k: fix NULL deref in change_sta_links for unready link

{
  "id": "cd58be9a11de1655ab409af7dde0e76112425e628cd206220f4e35297e16121b",
  "url": "https://osv.dev/vulnerability/CVE-2026-74366",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "wifi: ath12k: fix NULL deref in change_sta_links for unready link",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: wifi: ath12k: fix NULL deref in change_sta_links for unready link _ieee80211_set_active_links() calls _ieee80211_link_use_channel() for each newly-added link and WARN_ON_ONCE()s if it fails. The call uses assign_on_failure=true, which allows mac80211 to continue despite driver failures, but when a mac80211-level channel validation fails (e.g., combinations check, DFS, or no available radio), drv_assign_vif_chanctx() is never reached. Since ath12k_mac_vdev_create() is only called from that path, arvif->is_created remains false and arvif->ar remains NULL for the failed link. The subsequent drv_change_sta_links() call reaches ath12k_mac_op_change_sta_links(), which allocates an arsta and sets ahsta->links_map |= BIT(link_id) for the broken link before checking whether the link is ready. When the vdev was never created, only station_add() is skipped, but the link remains in links_map. Any subsequent operation iterating links_map and dereferencing arvif->ar without a NULL check will crash. Two observed examples are NULL deref in ath12k_mac_ml_station_remove() on disconnect and in ath12k_mac_op_set_key() when wpa_supplicant installs PTK keys. BUG: Unable to handle kernel NULL pointer dereference at 0x00000000 pc : ath12k_mac_station_post_remove+0x40/0xe8 [ath12k] Call trace: ath12k_mac_station_post_remove+0x40/0xe8 [ath12k] ath12k_mac_op_sta_state+0xb60/0x1720 [ath12k] drv_sta_state+0x100/0xbd8 [mac80211] __sta_inf",
    "evidence": "osv:CVE-2026-74366",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.40",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-74366",
      "aliases": [
        "CVE-2026-74366"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "a27fa6148dacc79451e523c2694bc0a673b1be05"
                },
                {
                  "fixed": "cfcea221db933295bf2cd75a7f80d441c7a51e28"
                },
                {
                  "fixed": "5f5be2aa3b6d730c51dd4f8b432f2ad72823e63f"
                },
                {
                  "fixed": "47809a7c8348bc4a332ccc26a37c7145a5f609f8"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74366.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.14.0"
                },
                {
                  "fixed": "6.18.40"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.1.5"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74366.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:38.011656442Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/47809a7c8348bc4a332ccc26a37c7145a5f609f8",
        "https://git.kernel.org/stable/c/5f5be2aa3b6d730c51dd4f8b432f2ad72823e63f",
        "https://git.kernel.org/stable/c/cfcea221db933295bf2cd75a7f80d441c7a51e28",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74366.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-74366",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74366.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-74366",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 505428,
  "published_at": "2026-08-15T05:58:48.264+00:00"
}