CVE-2023-3865 (GCVE-0-2023-3865)
Vulnerability from cvelistv5
Published
2025-08-16 13:27
Modified
2026-08-15 12:23
Severity ?
8.1 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9
Version: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9
Version: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9
Version: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2misc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3813eee5154d6a4c5875cb4444cb2b63bac8947f",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
              "lessThan": "c86211159bc3178b891e0d60e586a32c7b6a231b",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
              "lessThan": "58a9c41064df27632e780c5a3ae3e0e4284957d1",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
              "lessThan": "5fe7f7b78290638806211046a99f031ff26164e1",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2misc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.121",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.36",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.3.*",
              "status": "unaffected",
              "version": "6.3.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.4",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.121",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.36",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.3.10",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.4",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix out-of-bound read in smb2_write\n\nksmbd_smb2_check_message doesn\u0027t validate hdr-\u003eNextCommand. If\n-\u003eNextCommand is bigger than Offset + Length of smb2 write, It will\nallow oversized smb2 write length. It will cause OOB read in smb2_write."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "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."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-15T12:23:42.112Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3813eee5154d6a4c5875cb4444cb2b63bac8947f"
        },
        {
          "url": "https://git.kernel.org/stable/c/c86211159bc3178b891e0d60e586a32c7b6a231b"
        },
        {
          "url": "https://git.kernel.org/stable/c/58a9c41064df27632e780c5a3ae3e0e4284957d1"
        },
        {
          "url": "https://git.kernel.org/stable/c/5fe7f7b78290638806211046a99f031ff26164e1"
        }
      ],
      "title": "ksmbd: fix out-of-bound read in smb2_write",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-3865",
    "datePublished": "2025-08-16T13:27:56.403Z",
    "dateReserved": "2023-07-24T14:52:38.053Z",
    "dateUpdated": "2026-08-15T12:23:42.112Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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