CVE-2026-64140 (GCVE-0-2026-64140)

Vulnerability from cvelistv5 – Published: 2026-07-19 15:40 – Updated: 2026-07-20 13:43
VLAI
Title
ksmbd: fix null pointer dereference in proc_show_files()
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix null pointer dereference in proc_show_files() When a SMB2 client opens a file with a durable v2 handle and then issues SMB2 SESSION_LOGOFF, session_fd_check() clears fp->tcon = NULL on the reconnectable file pointer but leaves the fp registered in global_ft.idr until the durable scavenger fires (up to fp->durable_timeout seconds later). During that window any read of /proc/fs/ksmbd/files (mode 0400) panics the kernel because proc_show_files() walks global_ft.idr and unconditionally dereferences fp->tcon->id with no NULL guard. Reproducer requires only a successful SMB2 SESSION_SETUP and a share configured with 'durable handles = yes'. KASAN report on mainline 70390501d194: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:proc_show_files+0x118/0x740 Call Trace: proc_show_files+0x118/0x740 seq_read_iter+0x4ef/0xe10 proc_reg_read_iter+0x1b7/0x280 ... Guard the dereference. A durable-disconnected fp legitimately has no tcon; report its tree id as 0 rather than oopsing.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: b38f99c1217ae04753340f0fdcd8f35bf56841dc , < 8eab081627b67216d1c8f638b68289b500dc9a6b (git)
Affected: b38f99c1217ae04753340f0fdcd8f35bf56841dc , < 904901561e61a2b559070b20c74a8c95491f30aa (git)
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Linux Linux Affected: 7.0
Unaffected: 0 , < 7.0 (semver)
Unaffected: 7.0.11 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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    "datePublished": "2026-07-19T15:40:33.194Z",
    "dateReserved": "2026-07-19T07:54:57.037Z",
    "dateUpdated": "2026-07-20T13:43:44.317Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
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      "current_release_date": "2026-07-21T08:07:16+00:00",
      "cve": "CVE-2026-64140",
      "id": "CVE-2026-64140",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_not_affected": "275",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ksmbd: fix null pointer dereference in proc_show_files()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64140.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

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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.