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CVE-2026-46195

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: validate dacloffset before building DACL pointers parse_sec_desc(), build_sec_desc(), and the chown path in id_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd before proving a DACL header fits inside the returned security descriptor. On 32-bit builds a malicious server can return dacloffset near U32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip past the later pointer-based bounds checks. build_sec_desc() and id_mode_to_cifs_acl() can then dereference DACL fields from the wrapped pointer in the chmod/chown rewrite paths. Validate dacloffset numerically before building any DACL pointer and reuse the same helper at the three DACL entry points.

Severity
CRITICAL
CVSS score
9.8 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-05-28 10:16:35.147000
Last modified
2026-10-19 20:18:37.523000
View original CVE JSON 
{
  "id": "CVE-2026-46195",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-05-28T10:16:35.147",
  "lastModified": "2026-10-19T20:18:37.523",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: validate dacloffset before building DACL pointers\n\nparse_sec_desc(), build_sec_desc(), and the chown path in\nid_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd\nbefore proving a DACL header fits inside the returned security\ndescriptor.\n\nOn 32-bit builds a malicious server can return dacloffset near\nU32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip\npast the later pointer-based bounds checks. build_sec_desc() and\nid_mode_to_cifs_acl() can then dereference DACL fields from the wrapped\npointer in the chmod/chown rewrite paths.\n\nValidate dacloffset numerically before building any DACL pointer and\nreuse the same helper at the three DACL entry points."
    }
  ],
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