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CVE-2023-3865 (GCVE-0-2023-3865)

Vulnerability from cvelistv5 – Published: 2025-08-16 13:27 – Updated: 2026-08-15 12:23
VLAI
Title
ksmbd: fix out-of-bound read in smb2_write
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix out-of-bound read in smb2_write ksmbd_smb2_check_message doesn't validate hdr->NextCommand. If ->NextCommand is bigger than Offset + Length of smb2 write, It will allow oversized smb2 write length. It will cause OOB read in smb2_write.
Severity
8.1 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 3813eee5154d6a4c5875cb4444cb2b63bac8947f (git)
Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < c86211159bc3178b891e0d60e586a32c7b6a231b (git)
Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 58a9c41064df27632e780c5a3ae3e0e4284957d1 (git)
Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 5fe7f7b78290638806211046a99f031ff26164e1 (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.15
Unaffected: 0 , < 5.15 (semver)
Unaffected: 5.15.121 , ≤ 5.15.* (semver)
Unaffected: 6.1.36 , ≤ 6.1.* (semver)
Unaffected: 6.3.10 , ≤ 6.3.* (semver)
Unaffected: 6.4 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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              "value": "AV:N - ksmbd is an in-kernel SMB server reachable over TCP/445; the bug is triggered by crafting SMB2 WRITE request fields (NextCommand/Length) sent from a remote SMB client.\nAC:L - The attacker fully controls NextCommand and Length in the SMB2 header/PDU and can reliably pass ksmbd_smb2_check_message by making them agree, with no race or other conditions outside attacker control.\nPR:L - smb2_write requires a valid SMB session, tree connect to a writable share, and an open file handle with write access; guest/basic share credentials suffice, but this is not a pre-authentication path.\nUI:N - Exploitation requires only attacker-sent SMB traffic; no victim user action such as opening a file or mounting a share is needed.\nS:U - Impact is confined to the host kernel running ksmbd; the vulnerability does not cross a VM, IOMMU, or other security authority boundary by itself.\nC:H - Oversized Length with a forged NextCommand causes smb2_write to kernel_write attacker-chosen lengths of memory past the request buffer into a share file the attacker can then read back, leaking large amounts of kernel memory (documented up to 64KiB).\nI:N - This is an out-of-bounds read only; it does not corrupt kernel memory or provide a write primitive into kernel structures.\nA:H - A large read past the kvmalloc\u0027d request buffer can touch unmapped memory and cause a kernel oops/panic, or otherwise disrupt the ksmbd worker path."
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    "dateReserved": "2023-07-24T14:52:38.053Z",
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    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-08-05T03:48:05+00:00",
      "cve": "CVE-2023-3865",
      "id": "CVE-2023-3865",
      "initial_release_date": "2023-07-28T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Out of bounds read in smb2_write",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2023/cve-2023-3865.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-09-02T01:57:23Z",
      "cve": "CVE-2023-3865",
      "id": "CVE-2023-3865",
      "initial_release_date": "2023-08-02T01:56:34Z",
      "product_status:known_not_affected": "404",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2023-3865",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2023-3865.json",
      "version": "18"
    }
  }
}



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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.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.