CVE-2026-64386 (GCVE-0-2026-64386)
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 query_info() replay double-free A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_query_info_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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        {
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          "programFiles": [
            "fs/smb/client/smb2pdu.c"
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              "versionType": "original_commit_for_fix"
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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 query_info() replay double-free\n\nA response-bearing attempt can return a replayable error and free its\nresponse buffer. If SMB2_query_info_init() fails before the next send,\ncleanup retains 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 - A malicious or compromised SMB2/3 server can remotely return a response-bearing replayable error and manipulate the subsequent connection state, reaching the vulnerable client over TCP.\nAC:L - The server controls the error response, disconnect, and reconnection sequence and can repeat it until the stale free occurs. Replay-enabled hard or retrans-configured SMB mounts are a reasonable deployment.\nPR:N - The malicious SMB peer needs no privileges or credentials on the client; SMB session setup authenticates the client to the server, not the attacker to the victim kernel.\nUI:N - Once the share is mounted, ordinary or automated file and metadata operations issue query-info requests, and exploitation requires no human action during the crafted response and reconnect sequence.\nS:U - The corruption and resulting impacts occur within the same Linux kernel security authority, without crossing a VM, sandbox, or IOMMU boundary.\nC:H - The double-free corrupts SMB response-buffer slab and mempool state, enabling aliased or use-after-free buffers that can be leveraged to expose kernel memory.\nI:H - Allocator freelist corruption and reuse of one buffer by concurrent SMB operations can provide attacker-controlled modification of live kernel memory and support control-flow hijacking.\nA:H - The repeated free can immediately cause allocator corruption, a BUG, kernel oops, or panic, and the malicious server can trigger the sequence repeatedly."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:54:38.353Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/100fb7c455fa86d248b8bd7bb9de757c192870b4"
        },
        {
          "url": "https://git.kernel.org/stable/c/3c81dda84799f76b42aec598564316e2964440db"
        },
        {
          "url": "https://git.kernel.org/stable/c/f1add4acb656f5a82806a1ab0e63fed3d8b1bfca"
        },
        {
          "url": "https://git.kernel.org/stable/c/89234773e8348918111aa15f6922b58cf3843364"
        },
        {
          "url": "https://git.kernel.org/stable/c/2a88561d66eb855813cf004a0abe648bbb17de5e"
        }
      ],
      "title": "smb: client: fix query_info() replay double-free",
      "x_generator": {
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64386",
    "datePublished": "2026-07-25T08:50:34.729Z",
    "dateReserved": "2026-07-19T15:36:31.784Z",
    "dateUpdated": "2026-08-17T04:54:38.353Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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