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CVE-2026-63866 (GCVE-0-2026-63866)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:04 – Updated: 2026-08-05 12:36
VLAI
Title
wifi: mt76: mt7996: Clear wcid pointer in mt7996_mac_sta_deinit_link()
Summary
In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7996: Clear wcid pointer in mt7996_mac_sta_deinit_link() Clear WCID pointer removing the sta link in mt7996_mac_sta_deinit_link routine.
Severity
8.8 (High)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: dd82a9e02c054052b5899872c1f32805428f6131 , < 455a48685feebf2d9c1656caad77f9ba1da7b06e (git)
Affected: dd82a9e02c054052b5899872c1f32805428f6131 , < c575459b485c47615491b1fd29f04b43fdc3da56 (git)
Affected: dd82a9e02c054052b5899872c1f32805428f6131 , < 88973240dc7c976dd320b36a9e6d925c9be083ae (git)
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Linux Linux Affected: 6.15
Unaffected: 0 , < 6.15 (semver)
Unaffected: 6.18.33 , ≤ 6.18.* (semver)
Unaffected: 7.0.10 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/wireless/mediatek/mt76/mt7996/main.c"
          ],
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              "versionType": "semver"
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                  "vulnerable": true
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                }
              ],
              "negate": false,
              "operator": "OR"
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        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: mt76: mt7996: Clear wcid pointer in mt7996_mac_sta_deinit_link()\n\nClear WCID pointer removing the sta link in mt7996_mac_sta_deinit_link\nroutine."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:A - The bug is in the MediaTek mt7996 WiFi driver and is reached when MLO station links are torn down via mac80211\u0027s change_sta_links callback, which a remote WiFi peer can trigger through 802.11be MLO association/reconfiguration (malicious AP to a client, or a malicious associated client to an AP/router).\nAC:L - An attacker who can complete or maintain an MLO WiFi session can deterministically trigger link removal/reconfiguration to hit mt7996_mac_sta_deinit_link(); no special memory layout or victim timing is required beyond normal MLO link churn the attacker controls.\nPR:N - Exploitation requires no local OS privileges on the victim; the attacker only needs to act as a WiFi peer (e.g., malicious AP or associated MLO client) to drive mac80211 link changes into the driver, not root/CAP_NET_ADMIN on the target host.\nUI:N - No victim user action beyond normal automatic WiFi operation is required; link add/remove is driven by the attacker\u0027s 802.11 MLO signaling once the victim device is operating as a WiFi client or AP with MLO enabled.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the same kernel/host security boundary; this is not a VM escape, sandbox escape, or cross-authority boundary bypass.\nC:H - Failing to NULL the global dev-\u003emt76.wcid[idx] entry before mt76_wcid_mask_clear() and kfree_rcu() leaves a use-after-free; stale wcid pointers are dereferenced on RX/TX completion paths via mt76_wcid_ptr(), enabling arbitrary kernel memory reads.\nI:H - The dangling wcid pointer permits writes through subsequent TX/RX and wcid-based container_of lookups on freed mt7996_sta_link objects, giving attacker-influenced heap corruption primitives suitable for control-flow hijacking.\nA:H - Use of a freed wcid structure during packet TX completion or RX processing can cause kernel oops/panic or wedged WiFi subsystem, and UAF corruption alone satisfies High availability impact even before full exploitation."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:36:42.414Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/455a48685feebf2d9c1656caad77f9ba1da7b06e"
        },
        {
          "url": "https://git.kernel.org/stable/c/c575459b485c47615491b1fd29f04b43fdc3da56"
        },
        {
          "url": "https://git.kernel.org/stable/c/88973240dc7c976dd320b36a9e6d925c9be083ae"
        }
      ],
      "title": "wifi: mt76: mt7996: Clear wcid pointer in mt7996_mac_sta_deinit_link()",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63866",
    "datePublished": "2026-07-19T14:04:51.806Z",
    "dateReserved": "2026-07-19T07:54:57.017Z",
    "dateUpdated": "2026-08-05T12:36:42.414Z",
    "state": "PUBLISHED"
  },
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    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-07-22T03:08:21+00:00",
      "cve": "CVE-2026-63866",
      "id": "CVE-2026-63866",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: wifi: mt76: mt7996: Clear wcid pointer in mt7996_mac_sta_deinit_link()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63866.json",
      "version": "3"
    }
  }
}



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Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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