FKIE_CVE-2026-46002

Vulnerability from fkie_nvd - Published: 2026-05-27 14:17 - Updated: 2026-05-27 14:48
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: ext2: reject inodes with zero i_nlink and valid mode in ext2_iget() ext2_iget() already rejects inodes with i_nlink == 0 when i_mode is zero or i_dtime is set, treating them as deleted. However, the case of i_nlink == 0 with a non-zero mode and zero dtime slips through. Since ext2 has no orphan list, such a combination can only result from filesystem corruption - a legitimate inode deletion always sets either i_dtime or clears i_mode before freeing the inode. A crafted image can exploit this gap to present such an inode to the VFS, which then triggers WARN_ON inside drop_nlink() (fs/inode.c) via ext2_unlink(), ext2_rename() and ext2_rmdir(): WARNING: CPU: 3 PID: 609 at fs/inode.c:336 drop_nlink+0xad/0xd0 fs/inode.c:336 CPU: 3 UID: 0 PID: 609 Comm: syz-executor Not tainted 6.12.77+ #1 Call Trace: <TASK> inode_dec_link_count include/linux/fs.h:2518 [inline] ext2_unlink+0x26c/0x300 fs/ext2/namei.c:295 vfs_unlink+0x2fc/0x9b0 fs/namei.c:4477 do_unlinkat+0x53e/0x730 fs/namei.c:4541 __x64_sys_unlink+0xc6/0x110 fs/namei.c:4587 do_syscall_64+0xf5/0x220 arch/x86/entry/common.c:78 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> WARNING: CPU: 0 PID: 646 at fs/inode.c:336 drop_nlink+0xad/0xd0 fs/inode.c:336 CPU: 0 UID: 0 PID: 646 Comm: syz.0.17 Not tainted 6.12.77+ #1 Call Trace: <TASK> inode_dec_link_count include/linux/fs.h:2518 [inline] ext2_rename+0x35e/0x850 fs/ext2/namei.c:374 vfs_rename+0xf2f/0x2060 fs/namei.c:5021 do_renameat2+0xbe2/0xd50 fs/namei.c:5178 __x64_sys_rename+0x7e/0xa0 fs/namei.c:5223 do_syscall_64+0xf5/0x220 arch/x86/entry/common.c:78 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> WARNING: CPU: 0 PID: 634 at fs/inode.c:336 drop_nlink+0xad/0xd0 fs/inode.c:336 CPU: 0 UID: 0 PID: 634 Comm: syz-executor Not tainted 6.12.77+ #1 Call Trace: <TASK> inode_dec_link_count include/linux/fs.h:2518 [inline] ext2_rmdir+0xca/0x110 fs/ext2/namei.c:311 vfs_rmdir+0x204/0x690 fs/namei.c:4348 do_rmdir+0x372/0x3e0 fs/namei.c:4407 __x64_sys_unlinkat+0xf0/0x130 fs/namei.c:4577 do_syscall_64+0xf5/0x220 arch/x86/entry/common.c:78 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> Extend the existing i_nlink == 0 check to also catch this case, reporting the corruption via ext2_error() and returning -EFSCORRUPTED. This rejects the inode at load time and prevents it from reaching any of the namei.c paths. Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/25947cc5b2374cd5bf627fe3141496444260d04f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2dde6377ab2e46bb80cf066c659ef016f3ad7a9b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/32e0b925572686399243834ec99e2a9d85c62eae
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/470264bbec499e276a89a6431144ae58f411ea4d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d3af04a43db86379df7438bf8bade71685b8a239
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\next2: reject inodes with zero i_nlink and valid mode in ext2_iget()\n\next2_iget() already rejects inodes with i_nlink == 0 when i_mode is\nzero or i_dtime is set, treating them as deleted. However, the case of\ni_nlink == 0 with a non-zero mode and zero dtime slips through. Since\next2 has no orphan list, such a combination can only result from\nfilesystem corruption - a legitimate inode deletion always sets either\ni_dtime or clears i_mode before freeing the inode.\n\nA crafted image can exploit this gap to present such an inode to the\nVFS, which then triggers WARN_ON inside drop_nlink() (fs/inode.c) via\next2_unlink(), ext2_rename() and ext2_rmdir():\n\nWARNING: CPU: 3 PID: 609 at fs/inode.c:336 drop_nlink+0xad/0xd0 fs/inode.c:336\nCPU: 3 UID: 0 PID: 609 Comm: syz-executor Not tainted 6.12.77+ #1\nCall Trace:\n \u003cTASK\u003e\n inode_dec_link_count include/linux/fs.h:2518 [inline]\n ext2_unlink+0x26c/0x300 fs/ext2/namei.c:295\n vfs_unlink+0x2fc/0x9b0 fs/namei.c:4477\n do_unlinkat+0x53e/0x730 fs/namei.c:4541\n __x64_sys_unlink+0xc6/0x110 fs/namei.c:4587\n do_syscall_64+0xf5/0x220 arch/x86/entry/common.c:78\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n \u003c/TASK\u003e\n\nWARNING: CPU: 0 PID: 646 at fs/inode.c:336 drop_nlink+0xad/0xd0 fs/inode.c:336\nCPU: 0 UID: 0 PID: 646 Comm: syz.0.17 Not tainted 6.12.77+ #1\nCall Trace:\n \u003cTASK\u003e\n inode_dec_link_count include/linux/fs.h:2518 [inline]\n ext2_rename+0x35e/0x850 fs/ext2/namei.c:374\n vfs_rename+0xf2f/0x2060 fs/namei.c:5021\n do_renameat2+0xbe2/0xd50 fs/namei.c:5178\n __x64_sys_rename+0x7e/0xa0 fs/namei.c:5223\n do_syscall_64+0xf5/0x220 arch/x86/entry/common.c:78\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n \u003c/TASK\u003e\n\nWARNING: CPU: 0 PID: 634 at fs/inode.c:336 drop_nlink+0xad/0xd0 fs/inode.c:336\nCPU: 0 UID: 0 PID: 634 Comm: syz-executor Not tainted 6.12.77+ #1\nCall Trace:\n \u003cTASK\u003e\n inode_dec_link_count include/linux/fs.h:2518 [inline]\n ext2_rmdir+0xca/0x110 fs/ext2/namei.c:311\n vfs_rmdir+0x204/0x690 fs/namei.c:4348\n do_rmdir+0x372/0x3e0 fs/namei.c:4407\n __x64_sys_unlinkat+0xf0/0x130 fs/namei.c:4577\n do_syscall_64+0xf5/0x220 arch/x86/entry/common.c:78\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n \u003c/TASK\u003e\n\nExtend the existing i_nlink == 0 check to also catch this case,\nreporting the corruption via ext2_error() and returning -EFSCORRUPTED.\nThis rejects the inode at load time and prevents it from reaching any\nof the namei.c paths.\n\nFound by Linux Verification Center (linuxtesting.org) with Syzkaller."
    }
  ],
  "id": "CVE-2026-46002",
  "lastModified": "2026-05-27T14:48:03.013",
  "metrics": {},
  "published": "2026-05-27T14:17:17.880",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/25947cc5b2374cd5bf627fe3141496444260d04f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2dde6377ab2e46bb80cf066c659ef016f3ad7a9b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/32e0b925572686399243834ec99e2a9d85c62eae"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/470264bbec499e276a89a6431144ae58f411ea4d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d3af04a43db86379df7438bf8bade71685b8a239"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.