CVE-2026-99272

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: validate the data area in SMB2_read() SMB2_read() copies le32_to_cpu(rsp->DataLength) bytes from (char *)rsp + rsp->DataOffset without checking that the range lies within the response actually received. A READ response with DataOffset == 0 makes smb2_get_data_area_len() zero the data length, so smb2_check_message() accepts a frame as short as the fixed response, while SMB2_read() still uses the server-supplied DataLength, capped only by CIFS_MAX_MSGSIZE and the caller's length. A malicious server can answer the synchronous read used by the mfsymlinks (or SFU) symlink parser with an 81-byte READ response carrying DataOffset 0 and DataLength 1067, making the client copy 1067 bytes from a 448-byte receive object (KASAN slab-out-of-bounds; up to 16 KiB in the general case). Clamp a zero (or header-overlapping) DataOffset to read_rsp_size, as handle_read_data() does for the asynchronous path, and reject the response unless DataOffset + DataLength fits within rsp_iov.iov_len. The SMB1 helper was fixed the same way in 5be5bdda5863.

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-11-07 14:17:02.477000

Last modified

2026-11-07 14:17:02.477000

View original CVE JSON

{
  "id": "CVE-2026-99272",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-11-07T14:17:02.477",
  "lastModified": "2026-11-07T14:17:02.477",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: validate the data area in SMB2_read()\n\nSMB2_read() copies le32_to_cpu(rsp->DataLength) bytes from\n(char *)rsp + rsp->DataOffset without checking that the range lies\nwithin the response actually received. A READ response with\nDataOffset == 0 makes smb2_get_data_area_len() zero the data length, so\nsmb2_check_message() accepts a frame as short as the fixed response,\nwhile SMB2_read() still uses the server-supplied DataLength, capped only\nby CIFS_MAX_MSGSIZE and the caller's length.\n\nA malicious server can answer the synchronous read used by the\nmfsymlinks (or SFU) symlink parser with an 81-byte READ response\ncarrying DataOffset 0 and DataLength 1067, making the client copy 1067\nbytes from a 448-byte receive object (KASAN slab-out-of-bounds; up to\n16 KiB in the general case).\n\nClamp a zero (or header-overlapping) DataOffset to read_rsp_size, as\nhandle_read_data() does for the asynchronous path, and reject the\nresponse unless DataOffset + DataLength fits within rsp_iov.iov_len.\nThe SMB1 helper was fixed the same way in 5be5bdda5863."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "fs/smb/client/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "d8e050398d23ef7c019c96200b80d73f4e5cec0c",
              "lessThan": "1ba1937de005e261a8858f45bfef5da7458df94c",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "d8e050398d23ef7c019c96200b80d73f4e5cec0c",
              "lessThan": "2ec9cdf469dd32bcf33073aeb30c08e9356e0ca1",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "fs/smb/client/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "3.7",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "3.7",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3.2",
              "lessThanOrEqual": "7.3.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.4-rc1",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1ba1937de005e261a8858f45bfef5da7458df94c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2ec9cdf469dd32bcf33073aeb30c08e9356e0ca1",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}