CVE-2026-64384 (GCVE-0-2026-64384)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:50 – Updated: 2026-08-05 12:41
VLAI
Title
smb: client: fix change notify replay double-free
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix change notify replay double-free A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_notify_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.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 433042a91f9373241307725b52de573933ffedbf , < 5821f9dbb8b5b24391850a13418e633edd0fb003 (git)
Affected: 4f1fffa2376922f3d1d506e49c0fd445b023a28e , < d684f4134998085702009b94c35c2003fc9e72d3 (git)
Affected: 4f1fffa2376922f3d1d506e49c0fd445b023a28e , < 52af1975f0dfae990c5a0e85872cc41be0e88a68 (git)
Affected: 4f1fffa2376922f3d1d506e49c0fd445b023a28e , < 901891513951bc8322ece754863909ea45af95c6 (git)
Affected: 4f1fffa2376922f3d1d506e49c0fd445b023a28e , < 145f820dcbb2cced374f2532f8a61a44dce4a615 (git)
Affected: 6.6.32 , < 6.6.145 (semver)
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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-rc1 , ≤ * (original_commit_for_fix)
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{
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix change notify replay double-free\n\nA response-bearing attempt can return a replayable error and free its\nresponse buffer. If SMB2_notify_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."
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            "baseSeverity": "CRITICAL",
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            "version": "3.1"
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              "value": "AV:N - A malicious SMB server can return a replayable response and then force reconnect failure over the network, causing the client to free stale response state twice.\nAC:L - The peer controls both prerequisites by returning a status such as STATUS_RETRY and then disconnecting or refusing reconnection; repeated attempts make the scheduling window attacker-controllable.\nPR:N - The malicious SMB peer requires no account, capability, or other privilege on the vulnerable client; the established client session does not grant the attacker privileges on that host.\nUI:N - An ordinary automated CIFS workload can maintain an outstanding change-notify request, after which the remote peer completes the trigger without human involvement.\nS:U - Exploitation compromises the kernel and resources governed by the same host security authority, without crossing a separate virtualization or sandbox boundary.\nC:H - The double-free corrupts the CIFS response-buffer slab or mempool, permitting overlapping live objects and freelist manipulation that can support disclosure of arbitrary kernel memory.\nI:H - The heap corruption can provide attacker-influenced writes through aliased request and response buffers or freelist poisoning, potentially enabling kernel control-flow hijacking.\nA:H - Hardened allocators can immediately panic on the consecutive double-free, while unhardened allocators can crash later through freelist corruption."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:41:20.802Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/145f820dcbb2cced374f2532f8a61a44dce4a615"
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      "title": "smb: client: fix change notify replay double-free",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64384",
    "datePublished": "2026-07-25T08:50:33.306Z",
    "dateReserved": "2026-07-19T15:36:31.784Z",
    "dateUpdated": "2026-08-05T12:41:20.802Z",
    "state": "PUBLISHED"
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    },
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      "cve": "CVE-2026-64384",
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      "product_status:known_affected": "1",
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      "status": "final",
      "title": "smb: client: fix change notify replay double-free",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-64384.json",
      "version": "2"
    },
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-28T03:00:00+00:00",
      "cve": "CVE-2026-64384",
      "id": "CVE-2026-64384",
      "initial_release_date": "2026-07-25T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "91",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: smb: client: fix change notify replay double-free",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64384.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • 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.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • 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.


Detection rules are retrieved from Rulezet.