CVE-2026-23230 (GCVE-0-2026-23230)

Vulnerability from cvelistv5 – Published: 2026-02-18 14:53 – Updated: 2026-02-23 03:16
VLAI?
Title
smb: client: split cached_fid bitfields to avoid shared-byte RMW races
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: split cached_fid bitfields to avoid shared-byte RMW races is_open, has_lease and on_list are stored in the same bitfield byte in struct cached_fid but are updated in different code paths that may run concurrently. Bitfield assignments generate byte read–modify–write operations (e.g. `orb $mask, addr` on x86_64), so updating one flag can restore stale values of the others. A possible interleaving is: CPU1: load old byte (has_lease=1, on_list=1) CPU2: clear both flags (store 0) CPU1: RMW store (old | IS_OPEN) -> reintroduces cleared bits To avoid this class of races, convert these flags to separate bool fields.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: ebe98f1447bbccf8228335c62d86af02a0ed23f7 , < 569fecc56bfe4df66f05734d67daef887746656b (git)
Affected: ebe98f1447bbccf8228335c62d86af02a0ed23f7 , < 4386f6af8aaedd0c5ad6f659b40cadcc8f423828 (git)
Affected: ebe98f1447bbccf8228335c62d86af02a0ed23f7 , < 3eaa22d688311c708b73f3c68bc6d0c8e3f0f77a (git)
Affected: ebe98f1447bbccf8228335c62d86af02a0ed23f7 , < c4b9edd55987384a1f201d3d07ff71e448d79c1b (git)
Affected: ebe98f1447bbccf8228335c62d86af02a0ed23f7 , < 4cfa4c37dcbcfd70866e856200ed8a2894cac578 (git)
Affected: ebe98f1447bbccf8228335c62d86af02a0ed23f7 , < ec306600d5ba7148c9dbf8f5a8f1f5c1a044a241 (git)
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    Linux Linux Affected: 6.1
Unaffected: 0 , < 6.1 (semver)
Unaffected: 6.1.164 , ≤ 6.1.* (semver)
Unaffected: 6.6.125 , ≤ 6.6.* (semver)
Unaffected: 6.12.72 , ≤ 6.12.* (semver)
Unaffected: 6.18.11 , ≤ 6.18.* (semver)
Unaffected: 6.19.1 , ≤ 6.19.* (semver)
Unaffected: 7.0-rc1 , ≤ * (original_commit_for_fix)
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{
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/cached_dir.h"
          ],
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              "status": "unaffected",
              "version": "6.18.11",
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              "status": "unaffected",
              "version": "6.19.1",
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            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0-rc1",
              "versionType": "original_commit_for_fix"
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      "cpeApplicability": [
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      "descriptions": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: split cached_fid bitfields to avoid shared-byte RMW races\n\nis_open, has_lease and on_list are stored in the same bitfield byte in\nstruct cached_fid but are updated in different code paths that may run\nconcurrently. Bitfield assignments generate byte read\u2013modify\u2013write\noperations (e.g. `orb $mask, addr` on x86_64), so updating one flag can\nrestore stale values of the others.\n\nA possible interleaving is:\n    CPU1: load old byte (has_lease=1, on_list=1)\n    CPU2: clear both flags (store 0)\n    CPU1: RMW store (old | IS_OPEN) -\u003e reintroduces cleared bits\n\nTo avoid this class of races, convert these flags to separate bool\nfields."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-23T03:16:44.194Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/569fecc56bfe4df66f05734d67daef887746656b"
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        {
          "url": "https://git.kernel.org/stable/c/4386f6af8aaedd0c5ad6f659b40cadcc8f423828"
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          "url": "https://git.kernel.org/stable/c/3eaa22d688311c708b73f3c68bc6d0c8e3f0f77a"
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          "url": "https://git.kernel.org/stable/c/c4b9edd55987384a1f201d3d07ff71e448d79c1b"
        },
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          "url": "https://git.kernel.org/stable/c/4cfa4c37dcbcfd70866e856200ed8a2894cac578"
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        {
          "url": "https://git.kernel.org/stable/c/ec306600d5ba7148c9dbf8f5a8f1f5c1a044a241"
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      ],
      "title": "smb: client: split cached_fid bitfields to avoid shared-byte RMW races",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23230",
    "datePublished": "2026-02-18T14:53:34.078Z",
    "dateReserved": "2026-01-13T15:37:45.988Z",
    "dateUpdated": "2026-02-23T03:16:44.194Z",
    "state": "PUBLISHED"
  },
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  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-23230\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-02-18T16:22:32.807\",\"lastModified\":\"2026-02-23T04:16:01.873\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nsmb: client: split cached_fid bitfields to avoid shared-byte RMW races\\n\\nis_open, has_lease and on_list are stored in the same bitfield byte in\\nstruct cached_fid but are updated in different code paths that may run\\nconcurrently. Bitfield assignments generate byte read\u2013modify\u2013write\\noperations (e.g. `orb $mask, addr` on x86_64), so updating one flag can\\nrestore stale values of the others.\\n\\nA possible interleaving is:\\n    CPU1: load old byte (has_lease=1, on_list=1)\\n    CPU2: clear both flags (store 0)\\n    CPU1: RMW store (old | IS_OPEN) -\u003e reintroduces cleared bits\\n\\nTo avoid this class of races, convert these flags to separate bool\\nfields.\"},{\"lang\":\"es\",\"value\":\"Se ha resuelto la siguiente vulnerabilidad en el kernel de Linux:\\n\\nsmb: cliente: dividir los campos de bits de cached_fid para evitar condiciones de carrera RMW de bytes compartidos\\n\\nis_open, has_lease y on_list se almacenan en el mismo byte de campo de bits en la estructura cached_fid, pero se actualizan en diferentes rutas de c\u00f3digo que pueden ejecutarse concurrentemente. Las asignaciones de campos de bits generan operaciones de lectura-modificaci\u00f3n-escritura de bytes (p. ej., \u0027orb $mask, addr\u0027 en x86_64), por lo que al actualizar una bandera (flag) se puede restaurar valores obsoletos de las otras.\\n\\nUna posible intercalaci\u00f3n es:\\n    CPU1: carga el byte antiguo (has_lease=1, on_list=1)\\n    CPU2: borra ambas banderas (almacena 0)\\n    CPU1: almacena RMW (old | IS_OPEN) -\u0026gt; reintroduce los bits borrados\\n\\nPara evitar esta clase de condiciones de carrera, hay que convertir estas banderas a campos bool separados.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/3eaa22d688311c708b73f3c68bc6d0c8e3f0f77a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/4386f6af8aaedd0c5ad6f659b40cadcc8f423828\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/4cfa4c37dcbcfd70866e856200ed8a2894cac578\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/569fecc56bfe4df66f05734d67daef887746656b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c4b9edd55987384a1f201d3d07ff71e448d79c1b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ec306600d5ba7148c9dbf8f5a8f1f5c1a044a241\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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  • 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.
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  • 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.



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