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FKIE_CVE-2025-21999

Vulnerability from fkie_nvd - Published: 2025-04-03 08:15 - Updated: 2026-07-14 13:17
Summary
In the Linux kernel, the following vulnerability has been resolved: proc: fix UAF in proc_get_inode() Fix race between rmmod and /proc/XXX's inode instantiation. The bug is that pde->proc_ops don't belong to /proc, it belongs to a module, therefore dereferencing it after /proc entry has been registered is a bug unless use_pde/unuse_pde() pair has been used. use_pde/unuse_pde can be avoided (2 atomic ops!) because pde->proc_ops never changes so information necessary for inode instantiation can be saved _before_ proc_register() in PDE itself and used later, avoiding pde->proc_ops->... dereference. rmmod lookup sys_delete_module proc_lookup_de pde_get(de); proc_get_inode(dir->i_sb, de); mod->exit() proc_remove remove_proc_subtree proc_entry_rundown(de); free_module(mod); if (S_ISREG(inode->i_mode)) if (de->proc_ops->proc_read_iter) --> As module is already freed, will trigger UAF BUG: unable to handle page fault for address: fffffbfff80a702b PGD 817fc4067 P4D 817fc4067 PUD 817fc0067 PMD 102ef4067 PTE 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 26 UID: 0 PID: 2667 Comm: ls Tainted: G Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:proc_get_inode+0x302/0x6e0 RSP: 0018:ffff88811c837998 EFLAGS: 00010a06 RAX: dffffc0000000000 RBX: ffffffffc0538140 RCX: 0000000000000007 RDX: 1ffffffff80a702b RSI: 0000000000000001 RDI: ffffffffc0538158 RBP: ffff8881299a6000 R08: 0000000067bbe1e5 R09: 1ffff11023906f20 R10: ffffffffb560ca07 R11: ffffffffb2b43a58 R12: ffff888105bb78f0 R13: ffff888100518048 R14: ffff8881299a6004 R15: 0000000000000001 FS: 00007f95b9686840(0000) GS:ffff8883af100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffbfff80a702b CR3: 0000000117dd2000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> proc_lookup_de+0x11f/0x2e0 __lookup_slow+0x188/0x350 walk_component+0x2ab/0x4f0 path_lookupat+0x120/0x660 filename_lookup+0x1ce/0x560 vfs_statx+0xac/0x150 __do_sys_newstat+0x96/0x110 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e [adobriyan@gmail.com: don't do 2 atomic ops on the common path]

{
  "affected": [
    {
      "affectedData": [
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          "product": "Linux",
          "programFiles": [
            "fs/proc/generic.c",
            "fs/proc/inode.c",
            "fs/proc/internal.h",
            "include/linux/proc_fs.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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            {
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            },
            {
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            },
            {
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              "status": "affected",
              "version": "97a32539b9568bb653683349e5a76d02ff3c3e2c",
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            },
            {
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        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/proc/generic.c",
            "fs/proc/inode.c",
            "fs/proc/internal.h",
            "include/linux/proc_fs.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.6"
            },
            {
              "lessThan": "5.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.236",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.180",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.132",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.85",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.21",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.13.*",
              "status": "unaffected",
              "version": "6.13.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.14",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "affectedData": [
        {
          "defaultStatus": "unknown",
          "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
          "vendor": "Siemens",
          "versions": [
            {
              "lessThan": "*",
              "status": "affected",
              "version": "V3.1.6",
              "versionType": "custom"
            }
          ]
        },
        {
          "defaultStatus": "unknown",
          "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
          "vendor": "Siemens",
          "versions": [
            {
              "lessThan": "*",
              "status": "affected",
              "version": "V3.1.6",
              "versionType": "custom"
            }
          ]
        },
        {
          "defaultStatus": "unknown",
          "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
          "vendor": "Siemens",
          "versions": [
            {
              "lessThan": "*",
              "status": "affected",
              "version": "V3.1.6",
              "versionType": "custom"
            }
          ]
        },
        {
          "defaultStatus": "unknown",
          "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
          "vendor": "Siemens",
          "versions": [
            {
              "lessThan": "*",
              "status": "affected",
              "version": "V3.1.6",
              "versionType": "custom"
            }
          ]
        },
        {
          "defaultStatus": "unknown",
          "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
          "vendor": "Siemens",
          "versions": [
            {
              "lessThan": "*",
              "status": "affected",
              "version": "V3.1.6",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "D37319E3-8D34-4CCC-9B92-A411C571A016",
              "versionEndExcluding": "6.1.132",
              "versionStartIncluding": "2.6.23",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "BCB56F36-C998-496A-A2E4-D9E0BB3A5BFC",
              "versionEndExcluding": "6.6.85",
              "versionStartIncluding": "6.2",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "3B63C450-D73B-4A53-9861-98E25C16E842",
              "versionEndExcluding": "6.12.21",
              "versionStartIncluding": "6.7",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "FAECBE4D-58CF-4836-BBAB-5E28B800A778",
              "versionEndExcluding": "6.13.9",
              "versionStartIncluding": "6.13",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*",
              "matchCriteriaId": "186716B6-2B66-4BD0-852E-D48E71C0C85F",
              "vulnerable": true
            },
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              "matchCriteriaId": "0D3E781C-403A-498F-9DA9-ECEE50F41E75",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*",
              "matchCriteriaId": "66619FB8-0AAF-4166-B2CF-67B24143261D",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:*",
              "matchCriteriaId": "D3D6550E-6679-4560-902D-AF52DCFE905B",
              "vulnerable": true
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          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nproc: fix UAF in proc_get_inode()\n\nFix race between rmmod and /proc/XXX\u0027s inode instantiation.\n\nThe bug is that pde-\u003eproc_ops don\u0027t belong to /proc, it belongs to a\nmodule, therefore dereferencing it after /proc entry has been registered\nis a bug unless use_pde/unuse_pde() pair has been used.\n\nuse_pde/unuse_pde can be avoided (2 atomic ops!) because pde-\u003eproc_ops\nnever changes so information necessary for inode instantiation can be\nsaved _before_ proc_register() in PDE itself and used later, avoiding\npde-\u003eproc_ops-\u003e...  dereference.\n\n      rmmod                         lookup\nsys_delete_module\n                         proc_lookup_de\n\t\t\t   pde_get(de);\n\t\t\t   proc_get_inode(dir-\u003ei_sb, de);\n  mod-\u003eexit()\n    proc_remove\n      remove_proc_subtree\n       proc_entry_rundown(de);\n  free_module(mod);\n\n                               if (S_ISREG(inode-\u003ei_mode))\n\t                         if (de-\u003eproc_ops-\u003eproc_read_iter)\n                           --\u003e As module is already freed, will trigger UAF\n\nBUG: unable to handle page fault for address: fffffbfff80a702b\nPGD 817fc4067 P4D 817fc4067 PUD 817fc0067 PMD 102ef4067 PTE 0\nOops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI\nCPU: 26 UID: 0 PID: 2667 Comm: ls Tainted: G\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996)\nRIP: 0010:proc_get_inode+0x302/0x6e0\nRSP: 0018:ffff88811c837998 EFLAGS: 00010a06\nRAX: dffffc0000000000 RBX: ffffffffc0538140 RCX: 0000000000000007\nRDX: 1ffffffff80a702b RSI: 0000000000000001 RDI: ffffffffc0538158\nRBP: ffff8881299a6000 R08: 0000000067bbe1e5 R09: 1ffff11023906f20\nR10: ffffffffb560ca07 R11: ffffffffb2b43a58 R12: ffff888105bb78f0\nR13: ffff888100518048 R14: ffff8881299a6004 R15: 0000000000000001\nFS:  00007f95b9686840(0000) GS:ffff8883af100000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: fffffbfff80a702b CR3: 0000000117dd2000 CR4: 00000000000006f0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n \u003cTASK\u003e\n proc_lookup_de+0x11f/0x2e0\n __lookup_slow+0x188/0x350\n walk_component+0x2ab/0x4f0\n path_lookupat+0x120/0x660\n filename_lookup+0x1ce/0x560\n vfs_statx+0xac/0x150\n __do_sys_newstat+0x96/0x110\n do_syscall_64+0x5f/0x170\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\n[adobriyan@gmail.com: don\u0027t do 2 atomic ops on the common path]"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: proc: correcci\u00f3n de UAF en proc_get_inode(). Correcci\u00f3n de la competencia entre rmmod y la instanciaci\u00f3n de inodo de /proc/XXX. El error es que pde-\u0026gt;proc_ops no pertenece a /proc, sino a un m\u00f3dulo; por lo tanto, desreferenciarlo despu\u00e9s de registrar la entrada /proc es un error, a menos que se haya usado el par use_pde/unuse_pde(). Se puede evitar usar_pde/unuse_pde (\u00a12 operaciones at\u00f3micas!) porque pde-\u0026gt;proc_ops nunca cambia, de modo que la informaci\u00f3n necesaria para la instanciaci\u00f3n de inodo se puede guardar _antes_ de proc_register() en el propio PDE y usarse m\u00e1s tarde, evitando la desreferencia de pde-\u0026gt;proc_ops-\u0026gt;... . rmmod lookup sys_delete_module proc_lookup_de pde_get(de); proc_get_inode(dir-\u0026gt;i_sb, de); mod-\u0026gt;exit() proc_remove eliminar_sub\u00e1rbol_proc proc_entry_rundown(de); liberar_m\u00f3dulo(mod); if (S_ISREG(inode-\u0026gt;i_mode)) if (de-\u0026gt;proc_ops-\u0026gt;proc_read_iter) --\u0026gt; Como el m\u00f3dulo ya est\u00e1 liberado, se activar\u00e1 UAF ERROR: no se puede manejar el error de p\u00e1gina para la direcci\u00f3n: fffffbfff80a702b PGD 817fc4067 P4D 817fc4067 PUD 817fc0067 PMD 102ef4067 PTE 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 26 UID: 0 PID: 2667 Comm: ls Tainted: G Nombre del hardware: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:proc_get_inode+0x302/0x6e0 RSP: 0018:ffff88811c837998 EFLAGS: 00010a06 RAX: dffffc0000000000 RBX: fffffffc0538140 RCX: 0000000000000007 RDX: 1ffffffff80a702b RSI: 0000000000000001 RDI: ffffffffc0538158 RBP: ffff8881299a6000 R08: 0000000067bbe1e5 R09: 1ffff11023906f20 R10: ffffffffb560ca07 R11: ffffffffb2b43a58 R12: ffff888105bb78f0 R13: ffff888100518048 R14: ffff8881299a6004 R15: 0000000000000001 FS: 00007f95b9686840(0000) GS:ffff8883af100000(0000) knlGS:000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffbfff80a702b CR3: 0000000117dd2000 CR4: 00000000000006f0 DR0: 00000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Rastreo de llamadas:  proc_lookup_de+0x11f/0x2e0 __lookup_slow+0x188/0x350 walk_component+0x2ab/0x4f0 path_lookupat+0x120/0x660 filename_lookup+0x1ce/0x560 vfs_statx+0xac/0x150 __do_sys_newstat+0x96/0x110 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e [adobriyan@gmail.com: no realice 2 operaciones at\u00f3micas en la ruta com\u00fan]"
    }
  ],
  "id": "CVE-2025-21999",
  "lastModified": "2026-07-14T13:17:28.107",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2025-21999",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2025-04-03T15:26:31.372538Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2025-04-03T08:15:15.360",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4b0b8445b6fd41e6f62ac90547a0ea9d348de3fa"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/63b53198aff2e4e6c5866a4ff73c7891f958ffa4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/64dc7c68e040251d9ec6e989acb69f8f6ae4a10b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/654b33ada4ab5e926cd9c570196fefa7bec7c1df"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/966f331403dc3ed04ff64eaf3930cf1267965e53"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/eda279586e571b05dff44d48e05f8977ad05855d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/ede3e8ac90ae106f0b29cd759aadebc1568f1308"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"
    },
    {
      "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
      "url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}



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