{"id":"CVE-2021-47349","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-47349","generatedAt":"2026-10-27T21:49:01.851Z","title":"In the Linux kernel, the following vulnerability has been resolved: mwifiex: bring down link before deleting interface We can deadlock when rmmod'ing the driver or going through firmware reset, because the cfg80211_unregister_wdev() has to bring down…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmwifiex: bring down link before deleting interface\n\nWe can deadlock when rmmod'ing the driver or going through firmware\nreset, because the cfg80211_unregister_wdev() has to bring down the link\nfor us, ... which then grab the same wiphy lock.\n\nnl80211_del_interface() already handles a very similar case, with a nice\ndescription:\n\n        /*\n         * We hold RTNL, so this is safe, without RTNL opencount cannot\n         * reach 0, and thus the rdev cannot be deleted.\n         *\n         * We need to do it for the dev_close(), since that will call\n         * the netdev notifiers, and we need to acquire the mutex there\n         * but don't know if we get there from here or from some other\n         * place (e.g. \"ip link set ... down\").\n         */\n        mutex_unlock(&rdev->wiphy.mtx);\n...\n\nDo similarly for mwifiex teardown, by ensuring we bring the link down\nfirst.\n\nSample deadlock trace:\n\n[  247.103516] INFO: task rmmod:2119 blocked for more than 123 seconds.\n[  247.110630]       Not tainted 5.12.4 #5\n[  247.115796] \"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\" disables this message.\n[  247.124557] task:rmmod           state:D stack:    0 pid: 2119 ppid:  2114 flags:0x00400208\n[  247.133905] Call trace:\n[  247.136644]  __switch_to+0x130/0x170\n[  247.140643]  __schedule+0x714/0xa0c\n[  247.144548]  schedule_preempt_disabled+0x88/0xf4\n[  247.149714]  __mutex_lock_common+0x43c/0x750\n[  247.154496]  mutex_lock_nested+0x5c/0x68\n[  247.158884]  cfg80211_netdev_notifier_call+0x280/0x4e0 [cfg80211]\n[  247.165769]  raw_notifier_call_chain+0x4c/0x78\n[  247.170742]  call_netdevice_notifiers_info+0x68/0xa4\n[  247.176305]  __dev_close_many+0x7c/0x138\n[  247.180693]  dev_close_many+0x7c/0x10c\n[  247.184893]  unregister_netdevice_many+0xfc/0x654\n[  247.190158]  unregister_netdevice_queue+0xb4/0xe0\n[  247.195424]  _cfg80211_unregister_wdev+0xa4/0x204 [cfg80211]\n[  247.201816]  cfg80211_unregister_wdev+0x20/0x2c [cfg80211]\n[  247.208016]  mwifiex_del_virtual_intf+0xc8/0x188 [mwifiex]\n[  247.214174]  mwifiex_uninit_sw+0x158/0x1b0 [mwifiex]\n[  247.219747]  mwifiex_remove_card+0x38/0xa0 [mwifiex]\n[  247.225316]  mwifiex_pcie_remove+0xd0/0xe0 [mwifiex_pcie]\n[  247.231451]  pci_device_remove+0x50/0xe0\n[  247.235849]  device_release_driver_internal+0x110/0x1b0\n[  247.241701]  driver_detach+0x5c/0x9c\n[  247.245704]  bus_remove_driver+0x84/0xb8\n[  247.250095]  driver_unregister+0x3c/0x60\n[  247.254486]  pci_unregister_driver+0x2c/0x90\n[  247.259267]  cleanup_module+0x18/0xcdc [mwifiex_pcie]","published":"2024-05-21T15:15:21.000Z","lastModified":"2026-06-17T04:17:16.000Z","status":"Analyzed","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-667"],"affected":["linux/linux kernel"],"epss":{"score":0.00178,"percentile":0.07351,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.18%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/1f9482aa8d412b4ba06ce6ab8e333fb8ca29a06e","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/35af69c7c0490fdccfc159c6a87e4d1dc070838a","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a3041d39d3c14da97fa3476835aba043ba810cf0","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/1f9482aa8d412b4ba06ce6ab8e333fb8ca29a06e","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/35af69c7c0490fdccfc159c6a87e4d1dc070838a","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/a3041d39d3c14da97fa3476835aba043ba810cf0","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-47349","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}