CVE-2026-64385 (GCVE-0-2026-64385)
Vulnerability from cvelistv5
Published
2026-07-25 08:50
Modified
2026-08-17 04:54
Severity ?
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_ioctl() replay A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_ioctl_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.
References
Impacted products
Vendor Product Version
Linux Linux Version: 433042a91f9373241307725b52de573933ffedbf
Version: 4f1fffa2376922f3d1d506e49c0fd445b023a28e
Version: 4f1fffa2376922f3d1d506e49c0fd445b023a28e
Version: 4f1fffa2376922f3d1d506e49c0fd445b023a28e
Version: 4f1fffa2376922f3d1d506e49c0fd445b023a28e
Version: 6.6.32   ≤
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{
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          "programFiles": [
            "fs/smb/client/smb2pdu.c"
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      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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              "negate": false,
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix double-free in SMB2_ioctl() replay\n\nA response-bearing attempt can return a replayable error and free its\nresponse buffer. If SMB2_ioctl_init() fails before the next send, cleanup\nretains the previous buffer type and frees that response again.\n\nReset response bookkeeping before each attempt to prevent the stale free."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - An attacker-controlled SMB server can deliver crafted SMB2 IOCTL responses over TCP, including through the kernel\u0027s periodic interface-query FSCTL on an existing SMB3 mount.\nAC:L - On a hard or retrans-enabled mount, the server controls replayable statuses, response contents, disconnects, reconnects, and repeated attempts, allowing it to drive both sides of the triggering sequence.\nPR:N - The malicious SMB server needs no account or privilege on the target; victim mounting authority and client authentication do not grant or require attacker-side target privileges.\nUI:N - Once the share is mounted, kernel delayed work can automatically issue the affected FSCTL when the server advertises multichannel support, requiring no user action during exploitation.\nS:U - The memory corruption compromises resources governed by the same host-kernel security authority and does not inherently cross a VM, container, or IOMMU boundary.\nC:H - The response-buffer double-free can corrupt SLUB or mempool state and create dangling or overlapping live buffers, enabling use-after-free exploitation and kernel-memory disclosure.\nI:H - Attacker-controlled network data can overwrite aliased or freed buffers and poison allocator state, supporting arbitrary writes and control-flow hijacking.\nA:H - The duplicate free can trigger an allocator BUG or corrupt kernel heap state, causing an oops, panic, or complete system crash."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:54:37.258Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/0be4bc64882edaefaaee8d1e27d083643eb778e6"
        },
        {
          "url": "https://git.kernel.org/stable/c/96fcfc8ae7359346156e492ca610e830d2649ad6"
        },
        {
          "url": "https://git.kernel.org/stable/c/276c8efbc49f9303ac76d0d4deab7128581b0f3b"
        },
        {
          "url": "https://git.kernel.org/stable/c/fc65ffb4ef1bf540da16b17c225ae51091e07d72"
        },
        {
          "url": "https://git.kernel.org/stable/c/f9bbadb6c94583e3b4af1afc449bfceb1d1ddec9"
        }
      ],
      "title": "smb: client: fix double-free in SMB2_ioctl() replay",
      "x_generator": {
        "engine": "bippy-1.2.0"
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    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64385",
    "datePublished": "2026-07-25T08:50:33.997Z",
    "dateReserved": "2026-07-19T15:36:31.784Z",
    "dateUpdated": "2026-08-17T04:54:37.258Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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