GHSA-3969-JVQ7-CJF4
Vulnerability from github – Published: 2026-03-25 12:30 – Updated: 2026-05-22 03:30In 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).
{
"affected": [],
"aliases": [
"CVE-2026-23279"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-03-25T11:16:22Z",
"severity": "MODERATE"
},
"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": "2026-05-22T03:30:25Z",
"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/753ad20dcbe36b67088c7770d8fc357d7cc43e08"
},
{
"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/f061336f072ab03fd29270ae61fede46bf8fd69d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f5d8af683410a8c82e48b51291915bd612523d9a"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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