CVE-2025-38523 (GCVE-0-2025-38523)

Vulnerability from cvelistv5 – Published: 2025-08-16 11:12 – Updated: 2025-08-16 11:12
VLAI?
Summary
In the Linux kernel, the following vulnerability has been resolved: cifs: Fix the smbd_response slab to allow usercopy The handling of received data in the smbdirect client code involves using copy_to_iter() to copy data from the smbd_reponse struct's packet trailer to a folioq buffer provided by netfslib that encapsulates a chunk of pagecache. If, however, CONFIG_HARDENED_USERCOPY=y, this will result in the checks then performed in copy_to_iter() oopsing with something like the following: CIFS: Attempting to mount //172.31.9.1/test CIFS: VFS: RDMA transport established usercopy: Kernel memory exposure attempt detected from SLUB object 'smbd_response_0000000091e24ea1' (offset 81, size 63)! ------------[ cut here ]------------ kernel BUG at mm/usercopy.c:102! ... RIP: 0010:usercopy_abort+0x6c/0x80 ... Call Trace: <TASK> __check_heap_object+0xe3/0x120 __check_object_size+0x4dc/0x6d0 smbd_recv+0x77f/0xfe0 [cifs] cifs_readv_from_socket+0x276/0x8f0 [cifs] cifs_read_from_socket+0xcd/0x120 [cifs] cifs_demultiplex_thread+0x7e9/0x2d50 [cifs] kthread+0x396/0x830 ret_from_fork+0x2b8/0x3b0 ret_from_fork_asm+0x1a/0x30 The problem is that the smbd_response slab's packet field isn't marked as being permitted for usercopy. Fix this by passing parameters to kmem_slab_create() to indicate that copy_to_iter() is permitted from the packet region of the smbd_response slab objects, less the header space.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: ee4cdf7ba857a894ad1650d6ab77669cbbfa329e , < 87dcc7e33fc3dcb8ed32333cec016528b5bb6ce4 (git)
Affected: ee4cdf7ba857a894ad1650d6ab77669cbbfa329e , < f0dd353d47f7051afa98c6c60c7486831eb1a410 (git)
Affected: ee4cdf7ba857a894ad1650d6ab77669cbbfa329e , < 43e7e284fc77b710d899569360ea46fa3374ae22 (git)
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    Linux Linux Affected: 6.12
Unaffected: 0 , < 6.12 (semver)
Unaffected: 6.12.36 , ≤ 6.12.* (semver)
Unaffected: 6.15.8 , ≤ 6.15.* (semver)
Unaffected: 6.16 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/smbdirect.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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          "versions": [
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              "version": "6.15.8",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "6.16",
              "versionType": "original_commit_for_fix"
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      "cpeApplicability": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: Fix the smbd_response slab to allow usercopy\n\nThe handling of received data in the smbdirect client code involves using\ncopy_to_iter() to copy data from the smbd_reponse struct\u0027s packet trailer\nto a folioq buffer provided by netfslib that encapsulates a chunk of\npagecache.\n\nIf, however, CONFIG_HARDENED_USERCOPY=y, this will result in the checks\nthen performed in copy_to_iter() oopsing with something like the following:\n\n CIFS: Attempting to mount //172.31.9.1/test\n CIFS: VFS: RDMA transport established\n usercopy: Kernel memory exposure attempt detected from SLUB object \u0027smbd_response_0000000091e24ea1\u0027 (offset 81, size 63)!\n ------------[ cut here ]------------\n kernel BUG at mm/usercopy.c:102!\n ...\n RIP: 0010:usercopy_abort+0x6c/0x80\n ...\n Call Trace:\n  \u003cTASK\u003e\n  __check_heap_object+0xe3/0x120\n  __check_object_size+0x4dc/0x6d0\n  smbd_recv+0x77f/0xfe0 [cifs]\n  cifs_readv_from_socket+0x276/0x8f0 [cifs]\n  cifs_read_from_socket+0xcd/0x120 [cifs]\n  cifs_demultiplex_thread+0x7e9/0x2d50 [cifs]\n  kthread+0x396/0x830\n  ret_from_fork+0x2b8/0x3b0\n  ret_from_fork_asm+0x1a/0x30\n\nThe problem is that the smbd_response slab\u0027s packet field isn\u0027t marked as\nbeing permitted for usercopy.\n\nFix this by passing parameters to kmem_slab_create() to indicate that\ncopy_to_iter() is permitted from the packet region of the smbd_response\nslab objects, less the header space."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-08-16T11:12:17.254Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/f0dd353d47f7051afa98c6c60c7486831eb1a410"
        },
        {
          "url": "https://git.kernel.org/stable/c/43e7e284fc77b710d899569360ea46fa3374ae22"
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      ],
      "title": "cifs: Fix the smbd_response slab to allow usercopy",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2025-38523",
    "datePublished": "2025-08-16T11:12:17.254Z",
    "dateReserved": "2025-04-16T04:51:24.023Z",
    "dateUpdated": "2025-08-16T11:12:17.254Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-38523\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-08-16T12:15:27.667\",\"lastModified\":\"2025-11-18T21:53:29.273\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\ncifs: Fix the smbd_response slab to allow usercopy\\n\\nThe handling of received data in the smbdirect client code involves using\\ncopy_to_iter() to copy data from the smbd_reponse struct\u0027s packet trailer\\nto a folioq buffer provided by netfslib that encapsulates a chunk of\\npagecache.\\n\\nIf, however, CONFIG_HARDENED_USERCOPY=y, this will result in the checks\\nthen performed in copy_to_iter() oopsing with something like the following:\\n\\n CIFS: Attempting to mount //172.31.9.1/test\\n CIFS: VFS: RDMA transport established\\n usercopy: Kernel memory exposure attempt detected from SLUB object \u0027smbd_response_0000000091e24ea1\u0027 (offset 81, size 63)!\\n ------------[ cut here ]------------\\n kernel BUG at mm/usercopy.c:102!\\n ...\\n RIP: 0010:usercopy_abort+0x6c/0x80\\n ...\\n Call Trace:\\n  \u003cTASK\u003e\\n  __check_heap_object+0xe3/0x120\\n  __check_object_size+0x4dc/0x6d0\\n  smbd_recv+0x77f/0xfe0 [cifs]\\n  cifs_readv_from_socket+0x276/0x8f0 [cifs]\\n  cifs_read_from_socket+0xcd/0x120 [cifs]\\n  cifs_demultiplex_thread+0x7e9/0x2d50 [cifs]\\n  kthread+0x396/0x830\\n  ret_from_fork+0x2b8/0x3b0\\n  ret_from_fork_asm+0x1a/0x30\\n\\nThe problem is that the smbd_response slab\u0027s packet field isn\u0027t marked as\\nbeing permitted for usercopy.\\n\\nFix this by passing parameters to kmem_slab_create() to indicate that\\ncopy_to_iter() is permitted from the packet region of the smbd_response\\nslab objects, less the header space.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: cifs: Arreglar el slab smbd_response para permitir usercopy El manejo de los datos recibidos en el c\u00f3digo del cliente smbdirect implica usar copy_to_iter() para copiar datos del tr\u00e1iler de paquetes de la estructura smbd_reponse a un b\u00fafer folioq proporcionado por netfslib que encapsula un trozo de pagecache. Sin embargo, si CONFIG_HARDENED_USERCOPY=y, esto dar\u00e1 como resultado que las comprobaciones realizadas en copy_to_iter() generen un error similar a lo siguiente: CIFS: Intentando montar //172.31.9.1/test CIFS: VFS: Transporte RDMA establecido usercopy: \u00a1Intento de exposici\u00f3n de memoria del kernel detectado desde el objeto SLUB \u0027smbd_response_0000000091e24ea1\u0027 (desplazamiento 81, tama\u00f1o 63)!-----------[ cut here ]------------ kernel BUG at mm/usercopy.c:102! ... RIP: 0010:usercopy_abort+0x6c/0x80 ... Call Trace:  __check_heap_object+0xe3/0x120 __check_object_size+0x4dc/0x6d0 smbd_recv+0x77f/0xfe0 [cifs] cifs_readv_from_socket+0x276/0x8f0 [cifs] cifs_read_from_socket+0xcd/0x120 [cifs] cifs_demultiplex_thread+0x7e9/0x2d50 [cifs] kthread+0x396/0x830 ret_from_fork+0x2b8/0x3b0 ret_from_fork_asm+0x1a/0x30 El problema es que la respuesta smbd_response El campo de paquete de slab no est\u00e1 marcado como permitido para copia de usuario. Se soluciona pasando par\u00e1metros a kmem_slab_create() para indicar que se permite copy_to_iter() desde la regi\u00f3n de paquete de los objetos slab smbd_response, menos el espacio de encabezado.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":5.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-1188\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.12\",\"versionEndExcluding\":\"6.12.36\",\"matchCriteriaId\":\"64471BC5-89E0-43B3-8318-2D7EFF377CBD\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.13\",\"versionEndExcluding\":\"6.15.8\",\"matchCriteriaId\":\"C7AFE5B0-F3B1-4D30-B8BF-EDA0385C4746\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.16:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"6D4894DB-CCFE-4602-B1BF-3960B2E19A01\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.16:rc2:*:*:*:*:*:*\",\"matchCriteriaId\":\"09709862-E348-4378-8632-5A7813EDDC86\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.16:rc3:*:*:*:*:*:*\",\"matchCriteriaId\":\"415BF58A-8197-43F5-B3D7-D1D63057A26E\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/43e7e284fc77b710d899569360ea46fa3374ae22\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/87dcc7e33fc3dcb8ed32333cec016528b5bb6ce4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/f0dd353d47f7051afa98c6c60c7486831eb1a410\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]}]}}"
  }
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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