wifi: mt76: use kfree_rcu for offchannel link in mt76_put_vif_phy_link

{
  "id": "1348b7ebe7f6941168ba1d0f33a6d763606d05892b04b7e646cce30cf08941b4",
  "url": "https://osv.dev/vulnerability/CVE-2026-74325",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "wifi: mt76: use kfree_rcu for offchannel link in mt76_put_vif_phy_link",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: use kfree_rcu for offchannel link in mt76_put_vif_phy_link mt76_put_vif_phy_link() frees the offchannel mlink with plain kfree() after rcu_assign_pointer(NULL). However, rcu_assign_pointer only prevents future RCU readers from obtaining the pointer -- it does not wait for existing readers that already hold it via rcu_dereference. The TX datapath (e.g. mt7996_mac_write_txwi) dereferences mlink->wcid and mlink->idx under rcu_read_lock. If a TX softirq obtained the pointer via rcu_dereference just before the NULL assignment, it will dereference freed memory after the kfree. struct mt76_vif_link already contains an rcu_head field that is unused at this free site -- a developer oversight, since the adjacent kfree_rcu_mightsleep call for rx_sc in the same function shows the pattern was understood. Replace kfree(mlink) with kfree_rcu(mlink, rcu_head).",
    "evidence": "osv:CVE-2026-74325",
    "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": "high",
    "structured": {
      "id": "CVE-2026-74325",
      "aliases": [
        "CVE-2026-74325"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "a8f424c1287cc79a06c21816658feea87dfcb83f"
                },
                {
                  "fixed": "c7a83899203ed36696a2d35ddd03c0f522874a63"
                },
                {
                  "fixed": "50e700ac0edce72dee5c3a9755865d9423696ac7"
                },
                {
                  "fixed": "7fae097aa9a56c30febf539d72ef3773165d3aa3"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74325.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-2026-74325.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.259321714Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/50e700ac0edce72dee5c3a9755865d9423696ac7",
        "https://git.kernel.org/stable/c/7fae097aa9a56c30febf539d72ef3773165d3aa3",
        "https://git.kernel.org/stable/c/c7a83899203ed36696a2d35ddd03c0f522874a63",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74325.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-74325",
        "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-2026-74325.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-74325",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 519987,
  "published_at": "2026-08-15T05:58:20.236+00:00"
}