GHSA-X28C-5HRW-XMH5

Vulnerability from github – Published: 2026-07-19 12:30 – Updated: 2026-07-20 15:31
VLAI
Details

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

f2fs: fix to do sanity check on f2fs_get_node_folio_ra()

kernel BUG at fs/f2fs/file.c:845! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 5336 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:f2fs_do_truncate_blocks+0x1115/0x1140 fs/f2fs/file.c:845 Code: fc fc 90 0f 0b e8 8b 9d 9a fd 90 0f 0b e8 83 9d 9a fd 48 89 df 48 c7 c6 60 d1 1a 8c e8 54 f1 fc fc 90 0f 0b e8 6c 9d 9a fd 90 <0f> 0b e8 64 9d 9a fd 90 0f 0b 90 e9 93 fd ff ff e8 56 9d 9a fd 90 RSP: 0018:ffffc9000e4474c0 EFLAGS: 00010283 RAX: ffffffff842b1d34 RBX: 0000000000000003 RCX: 0000000000100000 RDX: ffffc9000f03a000 RSI: 0000000000035503 RDI: 0000000000035504 RBP: ffffc9000e447608 R08: ffff8880123b0000 R09: 0000000000000002 R10: 00000000fffffffe R11: 0000000000000002 R12: 0000000000000001 R13: 0000000000000000 R14: 1ffff92001c88ea0 R15: 00000000ffff039c FS: 00007f7e02ee36c0(0000) GS:ffff88808c887000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff0305c4000 CR3: 0000000012d4c000 CR4: 0000000000352ef0 Call Trace: f2fs_truncate_blocks+0x10a/0x300 fs/f2fs/file.c:882 f2fs_truncate+0x471/0x7c0 fs/f2fs/file.c:940 f2fs_evict_inode+0xa3f/0x1ac0 fs/f2fs/inode.c:907 evict+0x61e/0xb10 fs/inode.c:841 f2fs_fill_super+0x5f43/0x78f0 fs/f2fs/super.c:5224 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694 vfs_get_tree+0x92/0x2a0 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3758 [inline] do_new_mount+0x341/0xd30 fs/namespace.c:3834 do_mount fs/namespace.c:4167 [inline] __do_sys_mount fs/namespace.c:4383 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4360 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f

count = ADDRS_PER_PAGE(dn.node_folio, inode);

count -= dn.ofs_in_node;
f2fs_bug_on(sbi, count < 0);

The fuzz test will trigger above bug_on in f2fs.

The root cause should be: in the corrupted inode, there is a direct node which has the same ino and nid in its footer, so in f2fs_do_truncate_blocks(), after f2fs_get_dnode_of_data() finds such dnode: 1) ADDRS_PER_PAGE(dn.node_folio, inode) will return 923 2) once dn.ofs_in_node points to addr[923, 1017] Then it will trigger the system panic.

Let's introduce NODE_TYPE_NON_IXNODE to indicate current node should not be an inode or xattr node, and then use it in below path to detect inconsistent node chain in inode mapping table:

  • f2fs_do_truncate_blocks
  • f2fs_get_dnode_of_data
  • f2fs_get_node_folio_ra
  • __get_node_folio
    • f2fs_sanity_check_node_footer
    • case NODE_TYPE_NON_IXNODE -> check whether it is inode|xnode
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2026-63819"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-19T12:16:54Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to do sanity check on f2fs_get_node_folio_ra()\n\nkernel BUG at fs/f2fs/file.c:845!\nOops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\nCPU: 0 UID: 0 PID: 5336 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full)\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nRIP: 0010:f2fs_do_truncate_blocks+0x1115/0x1140 fs/f2fs/file.c:845\nCode: fc fc 90 0f 0b e8 8b 9d 9a fd 90 0f 0b e8 83 9d 9a fd 48 89 df 48 c7 c6 60 d1 1a 8c e8 54 f1 fc fc 90 0f 0b e8 6c 9d 9a fd 90 \u003c0f\u003e 0b e8 64 9d 9a fd 90 0f 0b 90 e9 93 fd ff ff e8 56 9d 9a fd 90\nRSP: 0018:ffffc9000e4474c0 EFLAGS: 00010283\nRAX: ffffffff842b1d34 RBX: 0000000000000003 RCX: 0000000000100000\nRDX: ffffc9000f03a000 RSI: 0000000000035503 RDI: 0000000000035504\nRBP: ffffc9000e447608 R08: ffff8880123b0000 R09: 0000000000000002\nR10: 00000000fffffffe R11: 0000000000000002 R12: 0000000000000001\nR13: 0000000000000000 R14: 1ffff92001c88ea0 R15: 00000000ffff039c\nFS:  00007f7e02ee36c0(0000) GS:ffff88808c887000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007ff0305c4000 CR3: 0000000012d4c000 CR4: 0000000000352ef0\nCall Trace:\n \u003cTASK\u003e\n f2fs_truncate_blocks+0x10a/0x300 fs/f2fs/file.c:882\n f2fs_truncate+0x471/0x7c0 fs/f2fs/file.c:940\n f2fs_evict_inode+0xa3f/0x1ac0 fs/f2fs/inode.c:907\n evict+0x61e/0xb10 fs/inode.c:841\n f2fs_fill_super+0x5f43/0x78f0 fs/f2fs/super.c:5224\n get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694\n vfs_get_tree+0x92/0x2a0 fs/super.c:1754\n fc_mount fs/namespace.c:1193 [inline]\n do_new_mount_fc fs/namespace.c:3758 [inline]\n do_new_mount+0x341/0xd30 fs/namespace.c:3834\n do_mount fs/namespace.c:4167 [inline]\n __do_sys_mount fs/namespace.c:4383 [inline]\n __se_sys_mount+0x31d/0x420 fs/namespace.c:4360\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n\tcount = ADDRS_PER_PAGE(dn.node_folio, inode);\n\n\tcount -= dn.ofs_in_node;\n\tf2fs_bug_on(sbi, count \u003c 0);\n\nThe fuzz test will trigger above bug_on in f2fs.\n\nThe root cause should be: in the corrupted inode, there is a direct node\nwhich has the same ino and nid in its footer, so in f2fs_do_truncate_blocks(),\nafter f2fs_get_dnode_of_data() finds such dnode:\n1) ADDRS_PER_PAGE(dn.node_folio, inode) will return 923\n2) once dn.ofs_in_node points to addr[923, 1017]\nThen it will trigger the system panic.\n\nLet\u0027s introduce NODE_TYPE_NON_IXNODE to indicate current node should\nnot be an inode or xattr node, and then use it in below path to detect\ninconsistent node chain in inode mapping table:\n\n- f2fs_do_truncate_blocks\n - f2fs_get_dnode_of_data\n  - f2fs_get_node_folio_ra\n   -  __get_node_folio\n    - f2fs_sanity_check_node_footer\n     - case NODE_TYPE_NON_IXNODE -\u003e check whether it is inode|xnode",
  "id": "GHSA-x28c-5hrw-xmh5",
  "modified": "2026-07-20T15:31:47Z",
  "published": "2026-07-19T12:30:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63819"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0cc21c1ffe15b4156b0bf744f32fd1faef0b7c73"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/406c28af75123432d38cf9bbaa6f1476f7b14770"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8712353ed80f87271d732297567dcdbe4b84e8c7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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