{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2021-47256",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-47256",
    "idYear": 2021,
    "status": "PUBLISHED",
    "publishedAt": "2024-05-21T14:19:50.777Z",
    "updatedAt": "2026-05-11T13:50:58.894Z",
    "importedAt": "2026-10-24T01:56:36.661Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "mm/memory-failure: make sure wait for page writeback in memory_failure",
      "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/memory-failure: make sure wait for page writeback in memory_failure\n\nOur syzkaller trigger the \"BUG_ON(!list_empty(&inode->i_wb_list))\" in\nclear_inode:\n\n  kernel BUG at fs/inode.c:519!\n  Internal error: Oops - BUG: 0 [#1] SMP\n  Modules linked in:\n  Process syz-executor.0 (pid: 249, stack limit = 0x00000000a12409d7)\n  CPU: 1 PID: 249 Comm: syz-executor.0 Not tainted 4.19.95\n  Hardware name: linux,dummy-virt (DT)\n  pstate: 80000005 (Nzcv daif -PAN -UAO)\n  pc : clear_inode+0x280/0x2a8\n  lr : clear_inode+0x280/0x2a8\n  Call trace:\n    clear_inode+0x280/0x2a8\n    ext4_clear_inode+0x38/0xe8\n    ext4_free_inode+0x130/0xc68\n    ext4_evict_inode+0xb20/0xcb8\n    evict+0x1a8/0x3c0\n    iput+0x344/0x460\n    do_unlinkat+0x260/0x410\n    __arm64_sys_unlinkat+0x6c/0xc0\n    el0_svc_common+0xdc/0x3b0\n    el0_svc_handler+0xf8/0x160\n    el0_svc+0x10/0x218\n  Kernel panic - not syncing: Fatal exception\n\nA crash dump of this problem show that someone called __munlock_pagevec\nto clear page LRU without lock_page: do_mmap -> mmap_region -> do_munmap\n-> munlock_vma_pages_range -> __munlock_pagevec.\n\nAs a result memory_failure will call identify_page_state without\nwait_on_page_writeback.  And after truncate_error_page clear the mapping\nof this page.  end_page_writeback won't call sb_clear_inode_writeback to\nclear inode->i_wb_list.  That will trigger BUG_ON in clear_inode!\n\nFix it by checking PageWriteback too to help determine should we skip\nwait_on_page_writeback.",
      "affected": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0bc1f8b0682caa39f45ce1e0228ebf43acb46111",
              "status": "affected",
              "versionType": "git",
              "lessThan": "d05267fd27a5c4f54e06daefa3035995d765ca0c"
            },
            {
              "version": "0bc1f8b0682caa39f45ce1e0228ebf43acb46111",
              "status": "affected",
              "versionType": "git",
              "lessThan": "6d210d547adc2218ef8b5bcf23518c5f2f1fd872"
            },
            {
              "version": "0bc1f8b0682caa39f45ce1e0228ebf43acb46111",
              "status": "affected",
              "versionType": "git",
              "lessThan": "566345aaabac853aa866f53a219c4b02a6beb527"
            },
            {
              "version": "0bc1f8b0682caa39f45ce1e0228ebf43acb46111",
              "status": "affected",
              "versionType": "git",
              "lessThan": "9e379da727a7a031be9b877cde7b9c34a0fb8306"
            },
            {
              "version": "0bc1f8b0682caa39f45ce1e0228ebf43acb46111",
              "status": "affected",
              "versionType": "git",
              "lessThan": "28788dc5c70597395b6b451dae4549bbaa8e2c56"
            },
            {
              "version": "0bc1f8b0682caa39f45ce1e0228ebf43acb46111",
              "status": "affected",
              "versionType": "git",
              "lessThan": "e8675d291ac007e1c636870db880f837a9ea112a"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "versions": [
            {
              "version": "3.16",
              "status": "affected"
            },
            {
              "version": "0",
              "status": "unaffected",
              "versionType": "semver",
              "lessThan": "3.16"
            },
            {
              "version": "4.14.238",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "4.14.*"
            },
            {
              "version": "4.19.196",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "4.19.*"
            },
            {
              "version": "5.4.128",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.4.*"
            },
            {
              "version": "5.10.46",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "version": "5.12.13",
              "status": "unaffected",
              "versionType": "semver",
              "lessThanOrEqual": "5.12.*"
            },
            {
              "version": "5.13",
              "status": "unaffected",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ]
        }
      ]
    }
  }
}