CVE-2026-31394

/* * Conceptual Proof of Concept for CVE-2026-31394 * This code demonstrates the logic flow to trigger the crash. * Requires a system with a wireless card supporting AP and AP_VLAN modes. */ #include <stdio.h> #include <stdlib.h> #include <string.h> // Simulating the steps to reproduce the vulnerability: // 1. Create a wireless Access Point (AP) interface. // 2. Create an AP_VLAN interface associated with the AP. // 3. Configure a 4addr WDS client (station) on the AP_VLAN interface. // 4. Trigger a Channel Switch Announcement (CSA) on the AP. void trigger_vulnerability() { printf("[+] Setting up AP interface...\n"); // system("iw dev wlan0 interface add wlan0-ap type __ap"); printf("[+] Adding AP_VLAN interface...\n"); // system("iw dev wlan0-ap interface add wlan0-vlan type __ap vlan 1"); printf("[+] Associating a 4addr WDS station to VLAN...\n"); // This sets up sta->sdata to point to the VLAN sdata printf("[+] Triggering Channel Switch (CSA)...\n"); // This invokes ieee80211_chan_bw_change(), which crashes // when iterating the VLAN station and accessing NULL chan. printf("[-] Kernel panic expected (NULL pointer dereference)\n"); } int main() { trigger_vulnerability(); return 0; }

{"cve": {"id": "CVE-2026-31394", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-04-03T16:16:37.597", "lastModified": "2026-05-20T15:08:26.533", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmac80211: fix crash in ieee80211_chan_bw_change for AP_VLAN stations\n\nieee80211_chan_bw_change() iterates all stations and accesses\nlink->reserved.oper via sta->sdata->link[link_id]. For stations on\nAP_VLAN interfaces (e.g. 4addr WDS clients), sta->sdata points to\nthe VLAN sdata, whose link never participates in chanctx reservations.\nThis leaves link->reserved.oper zero-initialized with chan == NULL,\ncausing a NULL pointer dereference in __ieee80211_sta_cap_rx_bw()\nwhen accessing chandef->chan->band during CSA.\n\nResolve the VLAN sdata to its parent AP sdata using get_bss_sdata()\nbefore accessing link data.\n\n[also change sta->sdata in ARRAY_SIZE even if it doesn't matter]"}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-476"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.12.78", "matchCriteriaId": "77CDBE06-9D74-42B8-997B-232CD9BBDC24"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13", "versionEndExcluding": "6.18.20", "matchCriteriaId": "E5571059-6552-48E7-9BEF-3E358C387171"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.10", "matchCriteriaId": "96D34333-38BE-4414-9E79-6EB764329581"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*", "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*", "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/3c6629e859a2211a1fbb4868f915413f80001ca5", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/5a86d4e920d9783a198e39cf53f0e410fba5fbd6", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/65c25b588994dd422fea73fa322de56e1ae4a33b", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/672e5229e1ecfc2a3509b53adcb914d8b024a853", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}