ext4: fix null-ptr-deref in ext4_write_info

{
  "id": "28c67df0cbd73e0d2bf1834ffd8d640b88b6271f9f3286a2ba6fe0734a7eeca1",
  "url": "https://osv.dev/vulnerability/CVE-2022-50344",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ext4: fix null-ptr-deref in ext4_write_info",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: ext4: fix null-ptr-deref in ext4_write_info I caught a null-ptr-deref bug as follows: ================================================================== KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f] CPU: 1 PID: 1589 Comm: umount Not tainted 5.10.0-02219-dirty #339 RIP: 0010:ext4_write_info+0x53/0x1b0 [...] Call Trace: dquot_writeback_dquots+0x341/0x9a0 ext4_sync_fs+0x19e/0x800 __sync_filesystem+0x83/0x100 sync_filesystem+0x89/0xf0 generic_shutdown_super+0x79/0x3e0 kill_block_super+0xa1/0x110 deactivate_locked_super+0xac/0x130 deactivate_super+0xb6/0xd0 cleanup_mnt+0x289/0x400 __cleanup_mnt+0x16/0x20 task_work_run+0x11c/0x1c0 exit_to_user_mode_prepare+0x203/0x210 syscall_exit_to_user_mode+0x5b/0x3a0 do_syscall_64+0x59/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xa9 ================================================================== Above issue may happen as follows: ------------------------------------- exit_to_user_mode_prepare task_work_run __cleanup_mnt cleanup_mnt deactivate_super deactivate_locked_super kill_block_super generic_shutdown_super shrink_dcache_for_umount dentry = sb->s_root sb->s_root = NULL <--- Here set NULL sync_filesystem __sync_filesystem sb->s_op->sync_fs > ext4_sync_fs dquot_writeback_dquots sb->dq_op->write_info > ext4_write_info ext4_journal_start(d_inode(sb->s_root), EXT4_HT_QUOTA, 2) d_inode(sb->s_root) s_root->d_inode <--- Null pointer dereference To solve th",
    "evidence": "osv:CVE-2022-50344",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.9.331",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "4.14.296",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "4.19.262",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.4.220",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.10.150",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.75",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.19.17",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.0.3",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2022-50344",
      "aliases": [
        "CVE-2022-50344"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                },
                {
                  "fixed": "dc451578446afd03c0c21913993c08898a691435"
                },
                {
                  "fixed": "f4b5ff0b794aa94afac7269c494550ca2f66511b"
                },
                {
                  "fixed": "947264e00c46de19a016fd81218118c708fed2f3"
                },
                {
                  "fixed": "3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4"
                },
                {
                  "fixed": "f34ab95162763cd7352f46df169296eec28b688d"
                },
                {
                  "fixed": "533c60a0b97cee5daab376933f486207e6680fb7"
                },
                {
                  "fixed": "4a657319cfabd6199fd0b7b65bbebf6ded7a11c1"
                },
                {
                  "fixed": "bb420e8afc854d2a1caaa23a0c129839acfb7888"
                },
                {
                  "fixed": "f9c1f248607d5546075d3f731e7607d5571f2b60"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-50344.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "3.6.0"
                },
                {
                  "fixed": "4.9.331"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.10.0"
                },
                {
                  "fixed": "4.14.296"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.15.0"
                },
                {
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "4.20.0"
                },
                {
                  "fixed": "5.4.220"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.5.0"
                },
                {
                  "fixed": "5.10.150"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "5.11.0"
                },
                {
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            },
            {
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                  "introduced": "5.16.0"
                },
                {
                  "fixed": "5.19.17"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.20.0"
                },
                {
                  "fixed": "6.0.3"
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              ]
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-50344.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:38.738757441Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/3638aa1c7d87c0ca0aef23cf58cae2c48e7daca4",
        "https://git.kernel.org/stable/c/4a657319cfabd6199fd0b7b65bbebf6ded7a11c1",
        "https://git.kernel.org/stable/c/533c60a0b97cee5daab376933f486207e6680fb7",
        "https://git.kernel.org/stable/c/947264e00c46de19a016fd81218118c708fed2f3",
        "https://git.kernel.org/stable/c/bb420e8afc854d2a1caaa23a0c129839acfb7888",
        "https://git.kernel.org/stable/c/dc451578446afd03c0c21913993c08898a691435",
        "https://git.kernel.org/stable/c/f34ab95162763cd7352f46df169296eec28b688d",
        "https://git.kernel.org/stable/c/f4b5ff0b794aa94afac7269c494550ca2f66511b",
        "https://git.kernel.org/stable/c/f9c1f248607d5546075d3f731e7607d5571f2b60",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50344.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2022-50344",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/50xxx/CVE-2022-50344.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2022-50344",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 505959,
  "published_at": "2025-09-16T16:11:23.345+00:00"
}