CVE-2026-31614 (GCVE-0-2026-31614)

Vulnerability from cvelistv5 – Published: 2026-04-24 14:42 – Updated: 2026-06-14 17:42
VLAI?
Title
smb: client: fix off-by-8 bounds check in check_wsl_eas()
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix off-by-8 bounds check in check_wsl_eas() The bounds check uses (u8 *)ea + nlen + 1 + vlen as the end of the EA name and value, but ea_data sits at offset sizeof(struct smb2_file_full_ea_info) = 8 from ea, not at offset 0. The strncmp() later reads ea->ea_data[0..nlen-1] and the value bytes follow at ea_data[nlen+1..nlen+vlen], so the actual end is ea->ea_data + nlen + 1 + vlen. Isn't pointer math fun? The earlier check (u8 *)ea > end - sizeof(*ea) only guarantees the 8-byte header is in bounds, but since the last EA is placed within 8 bytes of the end of the response, the name and value bytes are read past the end of iov. Fix this mess all up by using ea->ea_data as the base for the bounds check. An "untrusted" server can use this to leak up to 8 bytes of kernel heap into the EA name comparison and influence which WSL xattr the data is interpreted as.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 7449d736bbbd160c76b01b8fcdf72f58a8757d4b , < bfbc74df8bbe095b3ed68f6d4487b368af087890 (git)
Affected: ea41367b2a602f602ea6594fc4a310520dcc64f4 , < 5cc0574c84aa73946ade587c41e81757b8b01cb5 (git)
Affected: ea41367b2a602f602ea6594fc4a310520dcc64f4 , < b2b76d09a64c538c57006180103fc1841e8cfa66 (git)
Affected: ea41367b2a602f602ea6594fc4a310520dcc64f4 , < ba3ad159aa61810bbe0acaf39578b1ebfb6f1a18 (git)
Affected: ea41367b2a602f602ea6594fc4a310520dcc64f4 , < a893f1757d9a4009e4a8d7ceb2312142fe29cea4 (git)
Affected: ea41367b2a602f602ea6594fc4a310520dcc64f4 , < 3d8b9d06bd3ac4c6846f5498800b0f5f8062e53b (git)
Affected: 6.6.32 , < 6.6.136 (semver)
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    Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (semver)
Unaffected: 6.6.136 , ≤ 6.6.* (semver)
Unaffected: 6.12.83 , ≤ 6.12.* (semver)
Unaffected: 6.18.24 , ≤ 6.18.* (semver)
Unaffected: 6.19.14 , ≤ 6.19.* (semver)
Unaffected: 7.0.1 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
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      "cpeApplicability": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix off-by-8 bounds check in check_wsl_eas()\n\nThe bounds check uses (u8 *)ea + nlen + 1 + vlen as the end of the EA\nname and value, but ea_data sits at offset sizeof(struct\nsmb2_file_full_ea_info) = 8 from ea, not at offset 0.  The strncmp()\nlater reads ea-\u003eea_data[0..nlen-1] and the value bytes follow at\nea_data[nlen+1..nlen+vlen], so the actual end is ea-\u003eea_data + nlen + 1\n+ vlen.  Isn\u0027t pointer math fun?\n\nThe earlier check (u8 *)ea \u003e end - sizeof(*ea) only guarantees the\n8-byte header is in bounds, but since the last EA is placed within 8\nbytes of the end of the response, the name and value bytes are read past\nthe end of iov.\n\nFix this mess all up by using ea-\u003eea_data as the base for the bounds\ncheck.\n\nAn \"untrusted\" server can use this to leak up to 8 bytes of kernel heap\ninto the EA name comparison and influence which WSL xattr the data is\ninterpreted as."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-14T17:42:58.516Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/bfbc74df8bbe095b3ed68f6d4487b368af087890"
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        {
          "url": "https://git.kernel.org/stable/c/5cc0574c84aa73946ade587c41e81757b8b01cb5"
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          "url": "https://git.kernel.org/stable/c/b2b76d09a64c538c57006180103fc1841e8cfa66"
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        {
          "url": "https://git.kernel.org/stable/c/3d8b9d06bd3ac4c6846f5498800b0f5f8062e53b"
        }
      ],
      "title": "smb: client: fix off-by-8 bounds check in check_wsl_eas()",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31614",
    "datePublished": "2026-04-24T14:42:34.153Z",
    "dateReserved": "2026-03-09T15:48:24.123Z",
    "dateUpdated": "2026-06-14T17:42:58.516Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2"
}


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