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CVE-2026-74325 (GCVE-0-2026-74325)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:58 – Updated: 2026-08-17 05:45
VLAI
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).
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: a8f424c1287cc79a06c21816658feea87dfcb83f , < c7a83899203ed36696a2d35ddd03c0f522874a63 (git)
Affected: a8f424c1287cc79a06c21816658feea87dfcb83f , < 50e700ac0edce72dee5c3a9755865d9423696ac7 (git)
Affected: a8f424c1287cc79a06c21816658feea87dfcb83f , < 7fae097aa9a56c30febf539d72ef3773165d3aa3 (git)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/wireless/mediatek/mt76/channel.c"
          ],
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          "vendor": "Linux",
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              "status": "affected",
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              "versionType": "git"
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          "vendor": "Linux",
          "versions": [
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              "version": "7.1.5",
              "versionType": "semver"
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              "version": "7.2",
              "versionType": "original_commit_for_fix"
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        {
          "nodes": [
            {
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                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
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                  "vulnerable": true
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                {
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                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: mt76: use kfree_rcu for offchannel link in mt76_put_vif_phy_link\n\nmt76_put_vif_phy_link() frees the offchannel mlink with plain kfree()\nafter rcu_assign_pointer(NULL). However, rcu_assign_pointer only prevents\nfuture RCU readers from obtaining the pointer -- it does not wait for\nexisting readers that already hold it via rcu_dereference.\n\nThe TX datapath (e.g. mt7996_mac_write_txwi) dereferences mlink-\u003ewcid\nand mlink-\u003eidx under rcu_read_lock. If a TX softirq obtained the pointer\nvia rcu_dereference just before the NULL assignment, it will dereference\nfreed memory after the kfree.\n\nstruct mt76_vif_link already contains an rcu_head field that is unused at\nthis free site -- a developer oversight, since the adjacent\nkfree_rcu_mightsleep call for rx_sc in the same function shows the\npattern was understood.\n\nReplace kfree(mlink) with kfree_rcu(mlink, rcu_head)."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached only through local nl80211/genl paths (NL80211_CMD_REMAIN_ON_CHANNEL, CANCEL_REMAIN_ON_CHANNEL, TRIGGER_SCAN) that call mt76_put_vif_phy_link during ROC/scan teardown; remote WiFi frames cannot invoke this free path.\nAC:L - Exploitation is a race between ROC/scan completion freeing the offchannel mlink and the TX datapath still dereferencing it under RCU; an attacker with nl80211 access controls both sides by starting offchannel ops, queuing offchannel TX, and cancelling ROC concurrently.\nPR:L - Entry points require GENL_UNS_ADMIN_PERM (CAP_NET_ADMIN in the socket user namespace). Per CNA guidance this is Low because unprivileged users can obtain CAP_NET_ADMIN via user namespaces and drive ROC/scan on an mt76 multi-radio interface they control.\nUI:N - No victim interaction is required once the attacker can issue nl80211 ROC/scan commands and offchannel TX; exploitation does not depend on a user opening files, mounting filesystems, or clicking prompts.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the same OS security boundary; it does not cross VM, container, or IOMMU isolation boundaries on its own.\nC:H - This is a use-after-free of struct mt76_vif_link freed via kfree while TX paths such as mt7996_mac_write_txwi still rcu_dereference and read mlink fields; UAF enables heap grooming for arbitrary kernel memory disclosure.\nI:H - Freed mlink contents control TXWI fields (omac_idx, wmm_idx, band_idx, bss idx) passed to firmware DMA descriptors; UAF provides a practical path to corrupt kernel heap metadata and achieve arbitrary code execution.\nA:H - Dereferencing the freed offchannel_link in the TX worker/softirq path causes kernel oops or panic; UAF on a hot transmit path can crash multi-radio mt76 APs, routers, and client devices during P2P/scan offchannel operations."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:45:54.629Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/c7a83899203ed36696a2d35ddd03c0f522874a63"
        },
        {
          "url": "https://git.kernel.org/stable/c/50e700ac0edce72dee5c3a9755865d9423696ac7"
        },
        {
          "url": "https://git.kernel.org/stable/c/7fae097aa9a56c30febf539d72ef3773165d3aa3"
        }
      ],
      "title": "wifi: mt76: use kfree_rcu for offchannel link in mt76_put_vif_phy_link",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74325",
    "datePublished": "2026-08-15T05:58:20.236Z",
    "dateReserved": "2026-08-15T05:44:03.884Z",
    "dateUpdated": "2026-08-17T05:45:54.629Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-74325",
      "date": "2026-09-04",
      "epss": "0.00127",
      "percentile": "0.02661"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-74325\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-15T06:22:33.130\",\"lastModified\":\"2026-08-17T06:19:26.923\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nwifi: mt76: use kfree_rcu for offchannel link in mt76_put_vif_phy_link\\n\\nmt76_put_vif_phy_link() frees the offchannel mlink with plain kfree()\\nafter rcu_assign_pointer(NULL). However, rcu_assign_pointer only prevents\\nfuture RCU readers from obtaining the pointer -- it does not wait for\\nexisting readers that already hold it via rcu_dereference.\\n\\nThe TX datapath (e.g. mt7996_mac_write_txwi) dereferences mlink-\u003ewcid\\nand mlink-\u003eidx under rcu_read_lock. If a TX softirq obtained the pointer\\nvia rcu_dereference just before the NULL assignment, it will dereference\\nfreed memory after the kfree.\\n\\nstruct mt76_vif_link already contains an rcu_head field that is unused at\\nthis free site -- a developer oversight, since the adjacent\\nkfree_rcu_mightsleep call for rx_sc in the same function shows the\\npattern was understood.\\n\\nReplace kfree(mlink) with kfree_rcu(mlink, rcu_head).\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/net/wireless/mediatek/mt76/channel.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"a8f424c1287cc79a06c21816658feea87dfcb83f\",\"lessThan\":\"c7a83899203ed36696a2d35ddd03c0f522874a63\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"a8f424c1287cc79a06c21816658feea87dfcb83f\",\"lessThan\":\"50e700ac0edce72dee5c3a9755865d9423696ac7\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"a8f424c1287cc79a06c21816658feea87dfcb83f\",\"lessThan\":\"7fae097aa9a56c30febf539d72ef3773165d3aa3\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/net/wireless/mediatek/mt76/channel.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.14\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.14\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.40\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/50e700ac0edce72dee5c3a9755865d9423696ac7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7fae097aa9a56c30febf539d72ef3773165d3aa3\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c7a83899203ed36696a2d35ddd03c0f522874a63\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-20T17:19:02+00:00",
      "cve": "CVE-2026-74325",
      "id": "CVE-2026-74325",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: wifi: mt76: use kfree_rcu for offchannel link in mt76_put_vif_phy_link",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74325.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

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.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.