CVE-2026-64383 (GCVE-0-2026-64383)
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_flush() replay SMB2_flush() keeps its response buffer bookkeeping across replay attempts. If a replayable flush response is received and the retry then fails before cifs_send_recv() stores a replacement response, flush_exit will free the stale response pointer a second time. Reinitialize resp_buftype and rsp_iov at the top of the replay loop so cleanup only acts on response state produced by the current attempt. This fixes a double-free without changing replay handling for successful requests.
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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        {
          "defaultStatus": "unaffected",
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              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
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      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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              "negate": false,
              "operator": "OR"
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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_flush() replay\n\nSMB2_flush() keeps its response buffer bookkeeping across replay\nattempts. If a replayable flush response is received and the retry then\nfails before cifs_send_recv() stores a replacement response, flush_exit\nwill free the stale response pointer a second time.\n\nReinitialize resp_buftype and rsp_iov at the top of the replay loop so\ncleanup only acts on response state produced by the current attempt.\nThis fixes a double-free without changing replay handling for successful\nrequests."
        }
      ],
      "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 - A malicious or compromised SMB server can trigger the flaw through crafted replayable responses and connection failures over the network.\nAC:L - The server controls both the replayable error and subsequent reconnect failure, allowing repeated triggering without an uncontrollable race.\nPR:N - The attacking SMB endpoint requires no privileges on the client system once an SMB session and file handle exist.\nUI:N - An automatically mounted share and routine service-generated fsync, truncate, timestamp, or seek operations can reach SMB2_flush() without human participation.\nS:U - The memory corruption compromises resources governed by the same host kernel security authority.\nC:H - The response-buffer double-free can create overlapping CIFS slab allocations and use-after-free primitives capable of exposing arbitrary kernel memory.\nI:H - Allocator corruption and attacker-influenced overlapping network buffers can provide arbitrary-write or control-flow-hijacking primitives.\nA:H - The double-free can immediately trigger an allocator BUG, kernel oops, or panic and can be invoked repeatedly."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:54:35.045Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6e27f40b682a5e42a2daae3ce6d96f0e0e16dedb"
        },
        {
          "url": "https://git.kernel.org/stable/c/878757163eea684750107a31ea134c103863515d"
        },
        {
          "url": "https://git.kernel.org/stable/c/3407240cde132a4b72d6429a2625a09a2f78adaf"
        },
        {
          "url": "https://git.kernel.org/stable/c/013a9a3da46c5dabcf18f65ea6a47874ba12a15d"
        },
        {
          "url": "https://git.kernel.org/stable/c/4be31c943a3a27a5a0251dbb8f5cb89059ec3d5a"
        }
      ],
      "title": "smb: client: fix double-free in SMB2_flush() replay",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64383",
    "datePublished": "2026-07-25T08:50:32.634Z",
    "dateReserved": "2026-07-19T15:36:31.784Z",
    "dateUpdated": "2026-08-17T04:54:35.045Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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