{"id":"CVE-2026-99061","title":"wifi: brcmfmac: fix P2P device removal race in brcmf_detach()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: brcmfmac: fix P2P device removal race in brcmf_detach()\n\nWhen the driver is removed while the user space process that created\nthe P2P device (e.g. wpa_supplicant)…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 9831bcb987df4aff6a1d85975f1dda4c654f298d < 7b79131e357c4786765b20a994ad40d4d35f2163","Linux >= 9831bcb987df4aff6a1d85975f1dda4c654f298d < 2e0c8c60a11b3177e7432c71d41249e276a0825f","Linux >= 9831bcb987df4aff6a1d85975f1dda4c654f298d < eef16a74ff8ed2a838d6bb862bb2c7783fce7466","Linux >= 9831bcb987df4aff6a1d85975f1dda4c654f298d < 47ca6395a1d91545cc9403f9218bc61be941a0c3","Linux >= 9831bcb987df4aff6a1d85975f1dda4c654f298d < 08a3f02fea636e97a7422d1512f76dacdb5b0887","Linux 4.4"],"published":"2026-10-23","updated":"2026-10-23","sourceUpdated":"2026-10-23T12:22:59.770Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99061","references":[{"url":"https://git.kernel.org/stable/c/7b79131e357c4786765b20a994ad40d4d35f2163"},{"url":"https://git.kernel.org/stable/c/2e0c8c60a11b3177e7432c71d41249e276a0825f"},{"url":"https://git.kernel.org/stable/c/eef16a74ff8ed2a838d6bb862bb2c7783fce7466"},{"url":"https://git.kernel.org/stable/c/47ca6395a1d91545cc9403f9218bc61be941a0c3"},{"url":"https://git.kernel.org/stable/c/08a3f02fea636e97a7422d1512f76dacdb5b0887"}],"tags":["cve.org"],"ingestedAt":"2026-10-23T13:24:55.518Z","slug":"CVE-2026-99061","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nwifi: brcmfmac: fix P2P device removal race in brcmf_detach()\n\nWhen the driver is removed while the user space process that created\nthe P2P device (e.g. wpa_supplicant) is still exiting, the P2P device\ninterface is removed twice and the kernel crashes.\n\nThe two paths are:\n\n - wpa_supplicant, on exit, sends NL80211_CMD_DEL_INTERFACE for the P2P\n   device. nl80211_del_interface() holds RTNL and the wiphy mutex and\n   calls brcmf_p2p_del_vif(), which disables discovery and waits up to\n   1.5 s for BRCMF_E_IF_DEL. Then it calls brcmf_remove_interface(),\n   which unregisters the wdev and frees the vif and the ifp.\n\n - brcmf_detach() sets the bus down, so BRCMF_E_IF_DEL never arrives,\n   and calls brcmf_remove_interface(ifp, false) for the same ifp.\n   brcmf_p2p_ifp_removed() reads ifp->vif and then blocks on\n   rtnl_lock(). When brcmf_p2p_del_vif() releases RTNL, it calls\n   cfg80211_unregister_wdev() on the wdev that was already unregistered\n   and freed.\n\nThe second list_del_rcu() of wdev->list faults on LIST_POISON2:\n\n  brcmfmac: brcmf_p2p_del_vif delete P2P vif\n  brcmfmac: brcmf_p2p_deinit_discovery enter\n  brcmfmac: brcmf_p2p_del_vif P2P: GO_NEG_PHASE status cleared\n  brcmfmac: brcmf_detach Enter\n  brcmfmac: brcmf_bus_change_state 1 -> 0\n  brcmfmac: brcmf_remove_interface Enter, bsscfgidx=1, ifidx=0\n  brcmfmac: brcmf_del_if Enter, bsscfgidx=1, ifidx=0\n  brcmfmac: brcmf_p2p_ifp_removed P2P: device interface removed\n  [1.5 s later, brcmf_p2p_del_vif() timed out]\n  brcmfmac: brcmf_remove_interface Enter, bsscfgidx=1, ifidx=0\n  brcmfmac: brcmf_del_if Enter, bsscfgidx=1, ifidx=0\n  brcmfmac: brcmf_p2p_ifp_removed P2P: device interface removed\n  Unable to handle kernel paging request at virtual address dead000000000122\n  Internal error: Oops: 96000044 [#1] PREEMPT_RT SMP\n  pc : _cfg80211_unregister_wdev+0x6c/0x264 [cfg80211]\n  Call trace:\n   _cfg80211_unregister_wdev+0x6c/0x264 [cfg80211]\n   cfg80211_unregister_wdev+0x10/0x1c [cfg80211]\n   brcmf_p2p_ifp_removed+0x84/0xb0 [brcmfmac]\n   brcmf_remove_interface+0x1f4/0x254 [brcmfmac]\n   brcmf_detach+0x88/0x180 [brcmfmac]\n   brcmf_sdio_remove+0x90/0x7b0 [brcmfmac]\n   brcmf_sdiod_remove+0x20/0xa0 [brcmfmac]\n   brcmf_ops_sdio_remove+0xbc/0x12c [brcmfmac]\n   sdio_bus_remove+0x38/0x144\n   device_release_driver_internal+0x1e8/0x2c0\n   device_release_driver+0x14/0x20\n   brcmf_sdio_bus_remove+0x2c/0x40 [brcmfmac]\n   brcmf_fwvid_unregister_vendor+0xd8/0x170 [brcmfmac]\n   __exit_compat+0x18/0x418 [brcmfmac_cyw]\n   __arm64_sys_delete_module+0x1ac/0x244\n\nThe log was taken with debug=0x406 on an i.MX 8M Plus board with a\nCYW55513 (Sona IF513) on SDIO. The driver is the Ezurio backport of\nbrcmfmac from v6.18.22 on a 5.4-rt kernel. The code involved is the same\nin mainline.\n\nTo reproduce:\n\n  1. Start wpa_supplicant on wlan0 and let it associate. It creates the\n     P2P device (iw dev shows \"type P2P-device\").\n  2. Stop wpa_supplicant and remove the driver without waiting for\n     wpa_supplicant to exit:\n\n       kill $(pidof wpa_supplicant)\n       rmmod brcmfmac_cyw brcmfmac\n\nThe crash is reproducible on that board.\n\nFor the interface without a netdev (the P2P device), take RTNL and the\nwiphy mutex in brcmf_detach() before reading iflist, and remove it with\nlocked=true. If brcmf_p2p_del_vif() runs first, brcmf_detach() finds the\nslot empty. If brcmf_detach() runs first, nl80211 does not find the wdev\nany more. The interfaces with a netdev are removed as before, because\nbrcmf_del_if() takes RTNL on its own for the primary interface.\n\n## Affected\n\n- `Linux >= 9831bcb987df4aff6a1d85975f1dda4c654f298d < 7b79131e357c4786765b20a994ad40d4d35f2163`\n- `Linux >= 9831bcb987df4aff6a1d85975f1dda4c654f298d < 2e0c8c60a11b3177e7432c71d41249e276a0825f`\n- `Linux >= 9831bcb987df4aff6a1d85975f1dda4c654f298d < eef16a74ff8ed2a838d6bb862bb2c7783fce7466`\n- `Linux >= 9831bcb987df4aff6a1d85975f1dda4c654f298d < 47ca6395a1d91545cc9403f9218bc61be941a0c3`\n- `Linux >= 9831bcb987df4aff6a1d85975f1dda4c654f298d < 08a3f02fea636e97a7422d1512f76dacdb5b0887`\n- `Linux 4.4`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}