GHSA-63FR-CH28-F5VQ

Vulnerability from github – Published: 2026-09-24 18:31 – Updated: 2026-10-03 12:31
VLAI
Details

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

btrfs: tree-checker: validate INODE_REF's namelen

[BUG] A crafted btrfs image can trigger the following crash:

BUG: unable to handle page fault for address: ffffd1dc42884000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page CPU: 9 UID: 0 PID: 1034 Comm: poc Not tainted 7.1.0-rc4-custom+ #383 PREEMPT(full) 46af0a92938a63be7132e0dfd71e62327c51d5c2 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022 RIP: 0010:memcpy+0xc/0x10 Call Trace: read_extent_buffer+0xe4/0x100 [btrfs 3cf0785dd58fec8c5ff84633b772f17ce1f92a8f] btrfs_get_name+0x15e/0x1e0 [btrfs 3cf0785dd58fec8c5ff84633b772f17ce1f92a8f] reconnect_path+0x165/0x390 exportfs_decode_fh_raw+0x337/0x400 ? drop_caches_sysctl_handler+0xb0/0xb0 ---[ end trace 0000000000000000 ]--- RIP: 0010:memcpy+0xc/0x10 Kernel panic - not syncing: Fatal exception

[CAUSE] TThe crafted image has the following corrupted INODE_REF item:

     item 9 key (258 INODE_REF 257) itemoff 11544 itemsize 4106
        index 2 namelen 4096 name: d\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000

The itemsize matches the namelen, but the namelen is 4096, way larger than normal name length limit (BTRFS_NAME_LEN, 255).

Meanwhile the memory of the @name is only 255 byte sized, this will cause out-of-boundary access, and cause the above crash.

[FIX] Add extra namelen verification for INODE_REF, just like what we have done in ROOT_REF checks.

Now the crafted image can be rejected gracefully:

BTRFS critical (device dm-2): corrupt leaf: root=5 block=30572544 slot=14 ino=259, invalid inode ref name length, has 4096 expect [1, 255] BTRFS error (device dm-2): read time tree block corruption detected on logical 30572544 mirror 2

[ Rebase, add a Link: tag, add an simple cause analyze ]

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
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-93813"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-24T17:17:14Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: tree-checker: validate INODE_REF\u0027s namelen\n\n[BUG]\nA crafted btrfs image can trigger the following crash:\n\n  BUG: unable to handle page fault for address: ffffd1dc42884000\n  #PF: supervisor write access in kernel mode\n  #PF: error_code(0x0002) - not-present page\n  CPU: 9 UID: 0 PID: 1034 Comm: poc Not tainted 7.1.0-rc4-custom+ #383 PREEMPT(full)  46af0a92938a63be7132e0dfd71e62327c51d5c2\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022\n  RIP: 0010:memcpy+0xc/0x10\n  Call Trace:\n   \u003cTASK\u003e\n   read_extent_buffer+0xe4/0x100 [btrfs 3cf0785dd58fec8c5ff84633b772f17ce1f92a8f]\n   btrfs_get_name+0x15e/0x1e0 [btrfs 3cf0785dd58fec8c5ff84633b772f17ce1f92a8f]\n   reconnect_path+0x165/0x390\n   exportfs_decode_fh_raw+0x337/0x400\n   ? drop_caches_sysctl_handler+0xb0/0xb0\n   \u003c/TASK\u003e\n  ---[ end trace 0000000000000000 ]---\n  RIP: 0010:memcpy+0xc/0x10\n  Kernel panic - not syncing: Fatal exception\n\n[CAUSE]\nTThe crafted image has the following corrupted INODE_REF item:\n\n         item 9 key (258 INODE_REF 257) itemoff 11544 itemsize 4106\n         \tindex 2 namelen 4096 name: d\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\n\nThe itemsize matches the namelen, but the namelen is 4096, way larger\nthan normal name length limit (BTRFS_NAME_LEN, 255).\n\nMeanwhile the memory of the @name is only 255 byte sized, this will cause\nout-of-boundary access, and cause the above crash.\n\n[FIX]\nAdd extra namelen verification for INODE_REF, just like what we have\ndone in ROOT_REF checks.\n\nNow the crafted image can be rejected gracefully:\n\n BTRFS critical (device dm-2): corrupt leaf: root=5 block=30572544 slot=14 ino=259, invalid inode ref name length, has 4096 expect [1, 255]\n BTRFS error (device dm-2): read time tree block corruption detected on logical 30572544 mirror 2\n\n[ Rebase, add a Link: tag, add an simple cause analyze ]",
  "id": "GHSA-63fr-ch28-f5vq",
  "modified": "2026-10-03T12:31:10Z",
  "published": "2026-09-24T18:31:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93813"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3dc22abc21f5892406c09202fa2627196cc96967"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4cb41f07685f88ec724a375883bb0c731db8f6eb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/509d6a4d889e425f305461d8323a7b39ca6c121c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/60078a3e25c09d9d8fba828b0d81bb33e449a1b2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8f75c19892263bc0555fba922aefe103e841e86d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eeddee090b834a7d4b6a8214d2e3739e64c7a338"
    }
  ],
  "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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