FKIE_CVE-2026-31432

Vulnerability from fkie_nvd - Published: 2026-04-22 09:16 - Updated: 2026-04-23 16:17
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix OOB write in QUERY_INFO for compound requests When a compound request such as READ + QUERY_INFO(Security) is received, and the first command (READ) consumes most of the response buffer, ksmbd could write beyond the allocated buffer while building a security descriptor. The root cause was that smb2_get_info_sec() checked buffer space using ppntsd_size from xattr, while build_sec_desc() often synthesized a significantly larger descriptor from POSIX ACLs. This patch introduces smb_acl_sec_desc_scratch_len() to accurately compute the final descriptor size beforehand, performs proper buffer checking with smb2_calc_max_out_buf_len(), and uses exact-sized allocation + iov pinning.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/075ea208c648cc2bcd616295b711d3637c61de45
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/515c2daab46021221bdf406bef19bc90a44ec617
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d48c64fb80ad78b3dd29fb7d79b6ec7bd72bfc09
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fda9522ed6afaec45cabc198d8492270c394c7bc
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix OOB write in QUERY_INFO for compound requests\n\nWhen a compound request such as READ + QUERY_INFO(Security) is received,\nand the first command (READ) consumes most of the response buffer,\nksmbd could write beyond the allocated buffer while building a security\ndescriptor.\n\nThe root cause was that smb2_get_info_sec() checked buffer space using\nppntsd_size from xattr, while build_sec_desc() often synthesized a\nsignificantly larger descriptor from POSIX ACLs.\n\nThis patch introduces smb_acl_sec_desc_scratch_len() to accurately\ncompute the final descriptor size beforehand, performs proper buffer\nchecking with smb2_calc_max_out_buf_len(), and uses exact-sized\nallocation + iov pinning."
    }
  ],
  "id": "CVE-2026-31432",
  "lastModified": "2026-04-23T16:17:41.280",
  "metrics": {},
  "published": "2026-04-22T09:16:21.410",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/075ea208c648cc2bcd616295b711d3637c61de45"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/515c2daab46021221bdf406bef19bc90a44ec617"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d48c64fb80ad78b3dd29fb7d79b6ec7bd72bfc09"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fda9522ed6afaec45cabc198d8492270c394c7bc"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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