GHSA-3969-JVQ7-CJF4

Vulnerability from github – Published: 2026-03-25 12:30 – Updated: 2026-03-25 12:30
VLAI?
Details

In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211: fix NULL pointer dereference in mesh_rx_csa_frame()

In mesh_rx_csa_frame(), elems->mesh_chansw_params_ie is dereferenced at lines 1638 and 1642 without a prior NULL check:

ifmsh->chsw_ttl = elems->mesh_chansw_params_ie->mesh_ttl;
...
pre_value = le16_to_cpu(elems->mesh_chansw_params_ie->mesh_pre_value);

The mesh_matches_local() check above only validates the Mesh ID, Mesh Configuration, and Supported Rates IEs. It does not verify the presence of the Mesh Channel Switch Parameters IE (element ID 118). When a received CSA action frame omits that IE, ieee802_11_parse_elems() leaves elems->mesh_chansw_params_ie as NULL, and the unconditional dereference causes a kernel NULL pointer dereference.

A remote mesh peer with an established peer link (PLINK_ESTAB) can trigger this by sending a crafted SPECTRUM_MGMT/CHL_SWITCH action frame that includes a matching Mesh ID and Mesh Configuration IE but omits the Mesh Channel Switch Parameters IE. No authentication beyond the default open mesh peering is required.

Crash confirmed on kernel 6.17.0-5-generic via mac80211_hwsim:

BUG: kernel NULL pointer dereference, address: 0000000000000000 Oops: Oops: 0000 [#1] SMP NOPTI RIP: 0010:ieee80211_mesh_rx_queued_mgmt+0x143/0x2a0 [mac80211] CR2: 0000000000000000

Fix by adding a NULL check for mesh_chansw_params_ie after mesh_matches_local() returns, consistent with how other optional IEs are guarded throughout the mesh code.

The bug has been present since v3.13 (released 2014-01-19).

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{
  "affected": [],
  "aliases": [
    "CVE-2026-23279"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-25T11:16:22Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: mac80211: fix NULL pointer dereference in mesh_rx_csa_frame()\n\nIn mesh_rx_csa_frame(), elems-\u003emesh_chansw_params_ie is dereferenced\nat lines 1638 and 1642 without a prior NULL check:\n\n    ifmsh-\u003echsw_ttl = elems-\u003emesh_chansw_params_ie-\u003emesh_ttl;\n    ...\n    pre_value = le16_to_cpu(elems-\u003emesh_chansw_params_ie-\u003emesh_pre_value);\n\nThe mesh_matches_local() check above only validates the Mesh ID,\nMesh Configuration, and Supported Rates IEs.  It does not verify the\npresence of the Mesh Channel Switch Parameters IE (element ID 118).\nWhen a received CSA action frame omits that IE, ieee802_11_parse_elems()\nleaves elems-\u003emesh_chansw_params_ie as NULL, and the unconditional\ndereference causes a kernel NULL pointer dereference.\n\nA remote mesh peer with an established peer link (PLINK_ESTAB) can\ntrigger this by sending a crafted SPECTRUM_MGMT/CHL_SWITCH action frame\nthat includes a matching Mesh ID and Mesh Configuration IE but omits the\nMesh Channel Switch Parameters IE.  No authentication beyond the default\nopen mesh peering is required.\n\nCrash confirmed on kernel 6.17.0-5-generic via mac80211_hwsim:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000000\n  Oops: Oops: 0000 [#1] SMP NOPTI\n  RIP: 0010:ieee80211_mesh_rx_queued_mgmt+0x143/0x2a0 [mac80211]\n  CR2: 0000000000000000\n\nFix by adding a NULL check for mesh_chansw_params_ie after\nmesh_matches_local() returns, consistent with how other optional IEs\nare guarded throughout the mesh code.\n\nThe bug has been present since v3.13 (released 2014-01-19).",
  "id": "GHSA-3969-jvq7-cjf4",
  "modified": "2026-03-25T12:30:21Z",
  "published": "2026-03-25T12:30:21Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23279"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/017c1792525064a723971f0216e6ef86a8c7af11"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/22a9adea7e26d236406edc0ea00b54351dd56b9c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2b5f282b1b7241ef624c3399a1cdff0bb1a3eeab"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/be8b82c567fda86f2cbb43b7208825125bb31421"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cc6d5a3c0a854aeae00915fc5386570c86029c60"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f5d8af683410a8c82e48b51291915bd612523d9a"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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