CVE-2026-64383 (GCVE-0-2026-64383)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:50 – Updated: 2026-10-19 20:38
VLAI
Title
smb: client: fix double-free in SMB2_flush() replay
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.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-16 15:39 UTC
CWE
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7033 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 433042a91f9373241307725b52de573933ffedbf , < 6e27f40b682a5e42a2daae3ce6d96f0e0e16dedb (git)
Affected: 4f1fffa2376922f3d1d506e49c0fd445b023a28e , < 878757163eea684750107a31ea134c103863515d (git)
Affected: 4f1fffa2376922f3d1d506e49c0fd445b023a28e , < 3407240cde132a4b72d6429a2625a09a2f78adaf (git)
Affected: 4f1fffa2376922f3d1d506e49c0fd445b023a28e , < 013a9a3da46c5dabcf18f65ea6a47874ba12a15d (git)
Affected: 4f1fffa2376922f3d1d506e49c0fd445b023a28e , < 4be31c943a3a27a5a0251dbb8f5cb89059ec3d5a (git)
Affected: 6.6.32 , < 6.6.145 (semver)
guessed Create a notification for this product.
Linux Linux Affected: 6.8
Unaffected: 0 , < 6.8 (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.96 , ≤ 6.12.* (semver)
Unaffected: 6.18.39 , ≤ 6.18.* (semver)
Unaffected: 7.1.4 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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      "aggregate_severity": "Important",
      "current_release_date": "2026-10-29T14:40:29+00:00",
      "cve": "CVE-2026-64383",
      "id": "CVE-2026-64383",
      "initial_release_date": "2026-07-25T00:00:00+00:00",
      "product_status:fixed": "1224",
      "product_status:known_not_affected": "112",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: smb: client: fix double-free in SMB2_flush() replay",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64383.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-64383",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-10-16T15:39:52.688233Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "cweId": "CWE-415",
                    "description": "CWE-415 Double Free",
                    "lang": "en",
                    "type": "CWE"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-10-16T15:39:53.281Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
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              "product": "Linux",
              "programFiles": [
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              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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              "versions": [
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                },
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                  "status": "affected",
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                },
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                },
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                  "versionType": "git"
                },
                {
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                  "status": "affected",
                  "version": "6.6.32",
                  "versionType": "semver"
                }
              ]
            },
            {
              "defaultStatus": "affected",
              "product": "Linux",
              "programFiles": [
                "fs/smb/client/smb2pdu.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
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                  "status": "affected",
                  "version": "6.8"
                },
                {
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                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
                },
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                  "status": "unaffected",
                  "version": "6.6.145",
                  "versionType": "semver"
                },
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                  "lessThanOrEqual": "6.12.*",
                  "status": "unaffected",
                  "version": "6.12.96",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.18.*",
                  "status": "unaffected",
                  "version": "6.18.39",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "7.1.*",
                  "status": "unaffected",
                  "version": "7.1.4",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "*",
                  "status": "unaffected",
                  "version": "7.2",
                  "versionType": "original_commit_for_fix"
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              ]
            }
          ],
          "cpeApplicability": [
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              "nodes": [
                {
                  "cpeMatch": [
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                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.6.145",
                      "versionStartIncluding": "6.6.32",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.12.96",
                      "versionStartIncluding": "6.8",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                      "vulnerable": true
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                      "versionEndExcluding": "7.2",
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                  "operator": "OR"
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          "descriptions": [
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              "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."
            }
          ],
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                "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."
                }
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            "dateUpdated": "2026-08-17T04:54:35.045Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
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            {
              "url": "https://git.kernel.org/stable/c/4be31c943a3a27a5a0251dbb8f5cb89059ec3d5a"
            }
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          "title": "smb: client: fix double-free in SMB2_flush() replay",
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        "assignerShortName": "Linux",
        "cveId": "CVE-2026-64383",
        "datePublished": "2026-07-25T08:50:32.634Z",
        "dateReserved": "2026-07-19T15:36:31.784Z",
        "dateUpdated": "2026-10-19T20:38:26.139Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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