{"cve":"CVE-2021-47237","nvd":{"published":"2024-05-21T15:15:12.930","modified":"2026-06-17T04:16:58.720","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: hamradio: fix memory leak in mkiss_close\n\nMy local syzbot instance hit memory leak in\nmkiss_open()[1]. The problem was in missing\nfree_netdev() in mkiss_close().\n\nIn mkiss_open() netdevice is allocated and then\nregistered, but in mkiss_close() netdevice was\nonly unregistered, but not freed.\n\nFail log:\n\nBUG: memory leak\nunreferenced object 0xffff8880281ba000 (size 4096):\n  comm \"syz-executor.1\", pid 11443, jiffies 4295046091 (age 17.660s)\n  hex dump (first 32 bytes):\n    61 78 30 00 00 00 00 00 00 00 00 00 00 00 00 00  ax0.............\n    00 27 fa 2a 80 88 ff ff 00 00 00 00 00 00 00 00  .'.*............\n  backtrace:\n    [<ffffffff81a27201>] kvmalloc_node+0x61/0xf0\n    [<ffffffff8706e7e8>] alloc_netdev_mqs+0x98/0xe80\n    [<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1]\n    [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110\n    [<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670\n    [<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440\n    [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200\n    [<ffffffff8911263a>] do_syscall_64+0x3a/0xb0\n    [<ffffffff89200068>] entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nBUG: memory leak\nunreferenced object 0xffff8880141a9a00 (size 96):\n  comm \"syz-executor.1\", pid 11443, jiffies 4295046091 (age 17.660s)\n  hex dump (first 32 bytes):\n    e8 a2 1b 28 80 88 ff ff e8 a2 1b 28 80 88 ff ff  ...(.......(....\n    98 92 9c aa b0 40 02 00 00 00 00 00 00 00 00 00  .....@..........\n  backtrace:\n    [<ffffffff8709f68b>] __hw_addr_create_ex+0x5b/0x310\n    [<ffffffff8709fb38>] __hw_addr_add_ex+0x1f8/0x2b0\n    [<ffffffff870a0c7b>] dev_addr_init+0x10b/0x1f0\n    [<ffffffff8706e88b>] alloc_netdev_mqs+0x13b/0xe80\n    [<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1]\n    [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110\n    [<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670\n    [<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440\n    [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200\n    [<ffffffff8911263a>] do_syscall_64+0x3a/0xb0\n    [<ffffffff89200068>] entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nBUG: memory leak\nunreferenced object 0xffff8880219bfc00 (size 512):\n  comm \"syz-executor.1\", pid 11443, jiffies 4295046091 (age 17.660s)\n  hex dump (first 32 bytes):\n    00 a0 1b 28 80 88 ff ff 80 8f b1 8d ff ff ff ff  ...(............\n    80 8f b1 8d ff ff ff ff 00 00 00 00 00 00 00 00  ................\n  backtrace:\n    [<ffffffff81a27201>] kvmalloc_node+0x61/0xf0\n    [<ffffffff8706eec7>] alloc_netdev_mqs+0x777/0xe80\n    [<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1]\n    [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110\n    [<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670\n    [<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440\n    [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200\n    [<ffffffff8911263a>] do_syscall_64+0x3a/0xb0\n    [<ffffffff89200068>] entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nBUG: memory leak\nunreferenced object 0xffff888029b2b200 (size 256):\n  comm \"syz-executor.1\", pid 11443, jiffies 4295046091 (age 17.660s)\n  hex dump (first 32 bytes):\n    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................\n    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................\n  backtrace:\n    [<ffffffff81a27201>] kvmalloc_node+0x61/0xf0\n    [<ffffffff8706f062>] alloc_netdev_mqs+0x912/0xe80\n    [<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1]\n    [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110\n    [<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670\n    [<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440\n    [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200\n    [<ffffffff8911263a>] do_syscall_64+0x3a/0xb0\n    [<ffffffff89200068>] entry_SYSCALL_64_after_hwframe+0x44/0xae","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-401"],"references":["https://git.kernel.org/stable/c/290b0b6432e2599021db0b8d6046f756d931c29f","https://git.kernel.org/stable/c/3942d0f9ace1a95a74930b5b4fc0e5005c62b37b","https://git.kernel.org/stable/c/765a8a04f828db7222b36a42b1031f576bfe95c3","https://git.kernel.org/stable/c/7edcc682301492380fbdd604b4516af5ae667a13","https://git.kernel.org/stable/c/a49cbb762ef20655f5c91abdc13658b0af5e159d"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:50:30.954589733+00:00"},"epss":{"cve":"CVE-2021-47237","score":0.00226,"percentile":0.13359,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}