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GHSA-336V-J3X2-QMH8

Vulnerability from github – Published: 2025-11-12 12:30 – Updated: 2026-03-13 21:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

ext4: fix potential null deref in ext4_mb_init()

In ext4_mb_init(), ext4_mb_avg_fragment_size_destroy() may be called when sbi->s_mb_avg_fragment_size remains uninitialized (e.g., if groupinfo slab cache allocation fails). Since ext4_mb_avg_fragment_size_destroy() lacks null pointer checking, this leads to a null pointer dereference.

================================================================== EXT4-fs: no memory for groupinfo slab cache BUG: kernel NULL pointer dereference, address: 0000000000000000 PGD 0 P4D 0 Oops: Oops: 0002 [#1] SMP PTI CPU:2 UID: 0 PID: 87 Comm:mount Not tainted 6.17.0-rc2 #1134 PREEMPT(none) RIP: 0010:_raw_spin_lock_irqsave+0x1b/0x40 Call Trace: xa_destroy+0x61/0x130 ext4_mb_init+0x483/0x540 __ext4_fill_super+0x116d/0x17b0 ext4_fill_super+0xd3/0x280 get_tree_bdev_flags+0x132/0x1d0 vfs_get_tree+0x29/0xd0 do_new_mount+0x197/0x300 __x64_sys_mount+0x116/0x150 do_syscall_64+0x50/0x1c0 entry_SYSCALL_64_after_hwframe+0x76/0x7e ==================================================================

Therefore, add necessary null check to ext4_mb_avg_fragment_size_destroy() to prevent this issue. The same fix is also applied to ext4_mb_largest_free_orders_destroy().

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2025-40119"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-11-12T11:15:41Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix potential null deref in ext4_mb_init()\n\nIn ext4_mb_init(), ext4_mb_avg_fragment_size_destroy() may be called\nwhen sbi-\u003es_mb_avg_fragment_size remains uninitialized (e.g., if groupinfo\nslab cache allocation fails). Since ext4_mb_avg_fragment_size_destroy()\nlacks null pointer checking, this leads to a null pointer dereference.\n\n==================================================================\nEXT4-fs: no memory for groupinfo slab cache\nBUG: kernel NULL pointer dereference, address: 0000000000000000\nPGD 0 P4D 0\nOops: Oops: 0002 [#1] SMP PTI\nCPU:2 UID: 0 PID: 87 Comm:mount Not tainted 6.17.0-rc2 #1134 PREEMPT(none)\nRIP: 0010:_raw_spin_lock_irqsave+0x1b/0x40\nCall Trace:\n \u003cTASK\u003e\n xa_destroy+0x61/0x130\n ext4_mb_init+0x483/0x540\n __ext4_fill_super+0x116d/0x17b0\n ext4_fill_super+0xd3/0x280\n get_tree_bdev_flags+0x132/0x1d0\n vfs_get_tree+0x29/0xd0\n do_new_mount+0x197/0x300\n __x64_sys_mount+0x116/0x150\n do_syscall_64+0x50/0x1c0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n==================================================================\n\nTherefore, add necessary null check to ext4_mb_avg_fragment_size_destroy()\nto prevent this issue. The same fix is also applied to\next4_mb_largest_free_orders_destroy().",
  "id": "GHSA-336v-j3x2-qmh8",
  "modified": "2026-03-13T21:31:39Z",
  "published": "2025-11-12T12:30:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40119"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/00110f3cfc9b34b2dfee2a6c9e55a0ae6df125ae"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/08d9175578d6a8e9b81921898fbf01aa669cd2be"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3c3fac6bc0a9c00dbe65d8dc0d3a282afe4d3188"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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