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CVE-2026-46002

Estado: AnalizadaMedia (5.5)—

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():

Leer descripción completaMostrar menos

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.

Detalles técnicos trazas, registros y código del informe original
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>

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-46002",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
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              "versionType": "semver",
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              "version": "6.12.86",
              "versionType": "semver",
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              "versionType": "semver",
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              "versionType": "semver",
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  "published": "2026-05-27T14:17:17.880",
  "references": [
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "tags": [
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      "tags": [
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    },
    {
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      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "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 <TASK>\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 </TASK>\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 <TASK>\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 </TASK>\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 <TASK>\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 </TASK>\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."
    }
  ],
  "lastModified": "2026-06-17T10:52:52.770",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
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}