{"id":"CVE-2021-47638","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-47638","generatedAt":"2026-10-27T21:49:02.168Z","title":"In the Linux kernel, the following vulnerability has been resolved: ubifs: rename_whiteout: Fix double free for whiteout_ui->data 'whiteout_ui->data' will be freed twice if space budget fail for rename whiteout operation as following process:…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nubifs: rename_whiteout: Fix double free for whiteout_ui->data\n\n'whiteout_ui->data' will be freed twice if space budget fail for\nrename whiteout operation as following process:\n\nrename_whiteout\n  dev = kmalloc\n  whiteout_ui->data = dev\n  kfree(whiteout_ui->data)  // Free first time\n  iput(whiteout)\n    ubifs_free_inode\n      kfree(ui->data)\t    // Double free!\n\nKASAN reports:\n==================================================================\nBUG: KASAN: double-free or invalid-free in ubifs_free_inode+0x4f/0x70\nCall Trace:\n  kfree+0x117/0x490\n  ubifs_free_inode+0x4f/0x70 [ubifs]\n  i_callback+0x30/0x60\n  rcu_do_batch+0x366/0xac0\n  __do_softirq+0x133/0x57f\n\nAllocated by task 1506:\n  kmem_cache_alloc_trace+0x3c2/0x7a0\n  do_rename+0x9b7/0x1150 [ubifs]\n  ubifs_rename+0x106/0x1f0 [ubifs]\n  do_syscall_64+0x35/0x80\n\nFreed by task 1506:\n  kfree+0x117/0x490\n  do_rename.cold+0x53/0x8a [ubifs]\n  ubifs_rename+0x106/0x1f0 [ubifs]\n  do_syscall_64+0x35/0x80\n\nThe buggy address belongs to the object at ffff88810238bed8 which\nbelongs to the cache kmalloc-8 of size 8\n==================================================================\n\nLet ubifs_free_inode() free 'whiteout_ui->data'. BTW, delete unused\nassignment 'whiteout_ui->data_len = 0', process 'ubifs_evict_inode()\n-> ubifs_jnl_delete_inode() -> ubifs_jnl_write_inode()' doesn't need it\n(because 'inc_nlink(whiteout)' won't be excuted by 'goto out_release',\n and the nlink of whiteout inode is 0).","published":"2025-02-26T06:37:06.000Z","lastModified":"2026-08-04T10:17:12.000Z","status":"Modified","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-415"],"affected":["linux/linux kernel"],"epss":{"score":0.0026,"percentile":0.17615,"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 (0.26%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/14276d38c89a170363e90b6ac0a53c3cf61b87fc","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2ad07009c459e56ebdcc089d850d664660fdb742","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2b3236ecf96db7af5836e1366ce39ace8ce832fa","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/40a8f0d5e7b3999f096570edab71c345da812e3e","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6d7a158a7363c1f6604aa47ae1a280a5c65123dd","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8b3c7be16f3f4dfd6e15ac651484e59d3fa36274","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a90e2dbe66d2647ff95a0442ad2e86482d977fd8","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b9a937f096e608b3368c1abc920d4d640ba2c94f","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-47638","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."}