CVE-2022-50021

{
  "id": "CVE-2022-50021",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2025-06-18T11:15:30.280",
  "lastModified": "2026-11-05T20:17:20.920",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: block range must be validated before use in ext4_mb_clear_bb()\n\nBlock range to free is validated in ext4_free_blocks() using\next4_inode_block_valid() and then it's passed to ext4_mb_clear_bb().\nHowever in some situations on bigalloc file system the range might be\nadjusted after the validation in ext4_free_blocks() which can lead to\ntroubles on corrupted file systems such as one found by syzkaller that\nresulted in the following BUG\n\nkernel BUG at fs/ext4/ext4.h:3319!\nPREEMPT SMP NOPTI\nCPU: 28 PID: 4243 Comm: repro Kdump: loaded Not tainted 5.19.0-rc6+ #1\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1.fc35 04/01/2014\nRIP: 0010:ext4_free_blocks+0x95e/0xa90\nCall Trace:\n <TASK>\n ? lock_timer_base+0x61/0x80\n ? __es_remove_extent+0x5a/0x760\n ? __mod_timer+0x256/0x380\n ? ext4_ind_truncate_ensure_credits+0x90/0x220\n ext4_clear_blocks+0x107/0x1b0\n ext4_free_data+0x15b/0x170\n ext4_ind_truncate+0x214/0x2c0\n ? _raw_spin_unlock+0x15/0x30\n ? ext4_discard_preallocations+0x15a/0x410\n ? ext4_journal_check_start+0xe/0x90\n ? __ext4_journal_start_sb+0x2f/0x110\n ext4_truncate+0x1b5/0x460\n ? __ext4_journal_start_sb+0x2f/0x110\n ext4_evict_inode+0x2b4/0x6f0\n evict+0xd0/0x1d0\n ext4_enable_quotas+0x11f/0x1f0\n ext4_orphan_cleanup+0x3de/0x430\n ? proc_create_seq_private+0x43/0x50\n ext4_fill_super+0x295f/0x3ae0\n ? snprintf+0x39/0x40\n ? sget_fc+0x19c/0x330\n ? ext4_reconfigure+0x850/0x850\n get_tree_bdev+0x16d/0x260\n vfs_get_tree+0x25/0xb0\n path_mount+0x431/0xa70\n __x64_sys_mount+0xe2/0x120\n do_syscall_64+0x5b/0x80\n ? do_user_addr_fault+0x1e2/0x670\n ? exc_page_fault+0x70/0x170\n entry_SYSCALL_64_after_hwframe+0x46/0xb0\nRIP: 0033:0x7fdf4e512ace\n\nFix it by making sure that the block range is properly validated before\nused every time it changes in ext4_free_blocks() or ext4_mb_clear_bb()."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ext4: el rango de bloques debe validarse antes de su uso en ext4_mb_clear_bb(). El rango de bloques a liberar se valida en ext4_free_blocks() mediante ext4_inode_block_valid() y luego se pasa a ext4_mb_clear_bb(). Sin embargo, en algunas situaciones en el sistema de archivos bigalloc, el rango podría ajustarse después de la validación en ext4_free_blocks(), lo que puede causar problemas en sistemas de archivos dañados, como el detectado por syzkaller, que resultó en el siguiente error del kernel en fs/ext4/ext4.h:3319. PREEMPT SMP NOPTI CPU: 28 PID: 4243 Comm: repro Kdump: cargado No contaminado 5.19.0-rc6+ #1 Nombre del hardware: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1.fc35 01/04/2014 RIP: 0010:ext4_free_blocks+0x95e/0xa90 Rastreo de llamadas  ? lock_timer_base+0x61/0x80 ? __es_remove_extent+0x5a/0x760 ? __mod_timer+0x256/0x380 ? ext4_ind_truncate_ensure_credits+0x90/0x220 ext4_clear_blocks+0x107/0x1b0 ext4_free_data+0x15b/0x170 ext4_ind_truncate+0x214/0x2c0 ? _raw_spin_unlock+0x15/0x30 ? ext4_discard_preallocations+0x15a/0x410 ? ext4_journal_check_start+0xe/0x90 ? __ext4_journal_start_sb+0x2f/0x110 ext4_truncate+0x1b5/0x460 ? __ext4_journal_start_sb+0x2f/0x110 ext4_evict_inode+0x2b4/0x6f0 evict+0xd0/0x1d0 ext4_enable_quotas+0x11f/0x1f0 ext4_orphan_cleanup+0x3de/0x430 ? proc_create_seq_private+0x43/0x50 ext4_fill_super+0x295f/0x3ae0 ? snprintf+0x39/0x40 ? sget_fc+0x19c/0x330 ? ext4_reconfigure+0x850/0x850 get_tree_bdev+0x16d/0x260 vfs_get_tree+0x25/0xb0 path_mount+0x431/0xa70 __x64_sys_mount+0xe2/0x120 do_syscall_64+0x5b/0x80 ? do_user_addr_fault+0x1e2/0x670 ? exc_page_fault+0x70/0x170 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7fdf4e512ace Corríjalo asegurándose de que el rango de bloques esté validado correctamente antes de usarse cada vez que cambie en ext4_free_blocks() o ext4_mb_clear_bb()."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "fs/ext4/mballoc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
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              "lessThan": "7550aade978371ac582f6d43b14c4cb89ca54463",
              "versionType": "git",
              "status": "affected"
            },
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              "lessThan": "560a2744cbbf03cac65a6394f9b0d99aa437c867",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "84130193e0e6568dfdfb823f0e1e19aec80aff6e",
              "lessThan": "a2522041d248a8c969cbbc97e1fc2cd8b4de120d",
              "versionType": "git",
              "status": "affected"
            },
            {
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              "lessThan": "1e1c2b86ef86a8477fd9b9a4f48a6bfe235606f6",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "fs/ext4/mballoc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "3.2",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "3.2",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.10.175",
              "lessThanOrEqual": "5.10.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.15.103",
              "lessThanOrEqual": "5.15.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.19.4",
              "lessThanOrEqual": "5.19.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.0",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-11-05T19:53:08.795705Z",
          "id": "CVE-2022-50021",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    }
  ],
  "configurations": [
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      "nodes": [
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          "operator": "OR",
          "negate": false,
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      "url": "https://git.kernel.org/stable/c/1e1c2b86ef86a8477fd9b9a4f48a6bfe235606f6",
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