CVE-2026-90372 (GCVE-0-2026-90372)
Vulnerability from cvelistv5
Published
2026-09-17 16:09
Modified
2026-10-19 09:02
Severity ?
7.1 (High) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7915: avoid nss underflow in mt7915_mcu_get_sta_nss If a peer's VHT/HE MCS map has no supported spatial stream (all fields 0x3), the loop exits with nss == 0 and the function returned (u8)-1 (255), which was then written into the firmware sta_rec_bf beamforming fields. Clamp the result to 0.
References
Impacted products
Vendor Product Version
Linux Linux Version: 89029a85482cbcf68026a89fc974e8f6898d6b37
Version: 89029a85482cbcf68026a89fc974e8f6898d6b37
Version: 89029a85482cbcf68026a89fc974e8f6898d6b37
Version: 89029a85482cbcf68026a89fc974e8f6898d6b37
Version: 89029a85482cbcf68026a89fc974e8f6898d6b37
Version: 89029a85482cbcf68026a89fc974e8f6898d6b37
Version: 89029a85482cbcf68026a89fc974e8f6898d6b37
Version: 89029a85482cbcf68026a89fc974e8f6898d6b37
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/wireless/mediatek/mt76/mt7915/mcu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2801477c36a19be4f549fe60e54995f03b0ea7b9",
              "status": "affected",
              "version": "89029a85482cbcf68026a89fc974e8f6898d6b37",
              "versionType": "git"
            },
            {
              "lessThan": "38f4d6323bcd65e41a691432eddabd2b03acdeee",
              "status": "affected",
              "version": "89029a85482cbcf68026a89fc974e8f6898d6b37",
              "versionType": "git"
            },
            {
              "lessThan": "25f753f7f620955a8a51e63e445d8b9076c51396",
              "status": "affected",
              "version": "89029a85482cbcf68026a89fc974e8f6898d6b37",
              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "git"
            },
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            {
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              "versionType": "git"
            },
            {
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/wireless/mediatek/mt76/mt7915/mcu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.8"
            },
            {
              "lessThan": "5.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.270",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.221",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.188",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: mt76: mt7915: avoid nss underflow in mt7915_mcu_get_sta_nss\n\nIf a peer\u0027s VHT/HE MCS map has no supported spatial stream (all fields\n0x3), the loop exits with nss == 0 and the function returned (u8)-1 (255),\nwhich was then written into the firmware sta_rec_bf beamforming fields.\nClamp the result to 0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:A - A nearby 802.11 peer supplies the malformed MCS map in the HE Capabilities MCS NSS field of an Association Request. hostapd\u0027s NL80211_CMD_NEW_STATION reaches ieee80211_add_station()\u2192sta_link_apply_parameters(), which copies he_mcs_nss_supp; mt76_sta_state(AUTH\u2192ASSOC) then calls mt7915_mcu_get_sta_nss() on that map. WiFi radio range is Adjacent.\nAC:L - The attacker sets every 2-bit NSS field in HE rx_mcs_80 or rx_mcs_160 to 0x3. mt7915_mcu_get_sta_nss() then leaves its nss=8..1 loop with nss==0 and returns (u8)-1 (255) on every association. mac80211 does not reject an all-0x3 HE MCS map (unlike the 0xFFFF VHT check in ieee80211_vht_cap_ie_to_sta_vht_cap()). No race is involved.\nPR:N - mt7915_mac_sta_event(MT76_STA_EVENT_ASSOC) runs from sta_info_move_state(IEEE80211_STA_ASSOC) when hostapd\u0027s NL80211_CMD_NEW_STATION sets ASSOCIATED, before AUTHORIZED (the WPA 4-way handshake). 802.11 Open System authentication does not require a PSK or SAE credential on this path.\nUI:N - The attacker transmits the Association Request. ieee80211_add_station() and mt7915_mcu_add_sta() run in the AP kernel with no operator action on the victim device.\nS:U - The underflowed NSS is stored in the kernel sta_rec_bf TLV and sent to the on-device mt7915 MCU via MCU_EXT_CMD(STA_REC_UPDATE). Impact stays in the same kernel/device authority; this is not a VM, IOMMU, or sandbox escape.\nC:N - mt7915_mcu_get_sta_nss() only derives a u8 from the peer MCS map. That 255 is stored in sta_rec_bf.ncol_gt_bw80 or ibf_ncol; ncol used to index matrix[4][4] is min()\u0027d with nrow, so there is no kernel OOB read and nothing is returned over the air.\nI:L - mt7915_mcu_sta_bfer_he() writes the underflowed nss_mcs (255) directly to sta_rec_bf.ncol_gt_bw80 on 160 MHz, and the implicit-VHT path writes it to ibf_ncol, then mt7915_mcu_add_sta() sends that TLV to firmware. That is a limited corruption of the chip beamforming profile, not an arbitrary kernel write.\nA:H - ncol_gt_bw80 and ibf_ncol are NSS counts the mt7915 MCU uses as beamforming dimensions. 255 is far outside the 0\u20133 range implied by the driver\u0027s matrix[4][4], so the firmware can hang or crash and take the radio down, and the peer can retrigger it on every association."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:02:31.113Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2801477c36a19be4f549fe60e54995f03b0ea7b9"
        },
        {
          "url": "https://git.kernel.org/stable/c/38f4d6323bcd65e41a691432eddabd2b03acdeee"
        },
        {
          "url": "https://git.kernel.org/stable/c/25f753f7f620955a8a51e63e445d8b9076c51396"
        },
        {
          "url": "https://git.kernel.org/stable/c/e63c6291ecddf94769ab91f9d8cdb6ca939f7fc6"
        },
        {
          "url": "https://git.kernel.org/stable/c/85bd46ab7674b6d357f9a14791352c65fb09eee9"
        },
        {
          "url": "https://git.kernel.org/stable/c/6ce78d04c7ea4b66838941b5a4232dd1ee0e2cc7"
        },
        {
          "url": "https://git.kernel.org/stable/c/ecfd1a07e78c31d81322fb2d81dc468081cc3004"
        },
        {
          "url": "https://git.kernel.org/stable/c/4a2f4be532e3ea4e2b536e411793a05aaa51af25"
        }
      ],
      "title": "wifi: mt76: mt7915: avoid nss underflow in mt7915_mcu_get_sta_nss",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90372",
    "datePublished": "2026-09-17T16:09:12.733Z",
    "dateReserved": "2026-09-11T19:38:34.808Z",
    "dateUpdated": "2026-10-19T09:02:31.113Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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