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ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size smb_check_perm_dacl() validates that the DACL fits inside the NT security descriptor, but then bounds its two ACE walks by the remaining NTSD length (acl_size) rather than the DACL's declared size (pdacl_size). When pdacl->size is smaller than the trailing NTSD buffer, bytes after the declared DACL boundary - still inside the stored security descriptor - are parsed as ACEs during access checks. A crafted DACL can place an access-granting ACE beyond pdacl->size, and the current code accepts it during SMB2_CREATE access validation, while parse_dacl() and smb_inherit_dacl() stop at pdacl_size. Bound both ACE walks by pdacl_size to match the DACL boundary semantics used elsewhere in the server. Validation: - semantic KUnit harness shows the post-boundary ACE is selected before the fix and rejected (EACCES) after it - linux master (7.2-rc6), x86_64

Announced Group revision 1
Original source ↗

CVE-2026-90153

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-90153

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "8f0541186e9ad1b62accc9519cc2b7a7240272a7",
        "lessThan": "a2051ffe452afad52f580b85a3fd8851933b1e7c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "8f0541186e9ad1b62accc9519cc2b7a7240272a7",
        "lessThan": "a29f57a14c939586d84d7fd6a029bd1fd170098f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "8f0541186e9ad1b62accc9519cc2b7a7240272a7",
        "lessThan": "a4a307d149327dad5fb25187e1b03cebd1b04de6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "8f0541186e9ad1b62accc9519cc2b7a7240272a7",
        "lessThan": "8e4f75e979c1d9a51b0a48ac33d0cfd5f039ec67",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "8f0541186e9ad1b62accc9519cc2b7a7240272a7",
        "lessThan": "79decd88dd3f0d42e7fb0689b1a7853bfa302459",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "cb69d4d6f709f87c94afa28ae64c501576692171",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "6e8f4abf584253cbaa596ea4ad13110cf61cd4c9",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "8e33102309bd6839b2e2e158f93a7b378cb4655d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "5.15.62",
        "lessThan": "5.16",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "5.18.18",
        "lessThan": "5.19",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "5.19.2",
        "lessThan": "5.20",
        "versionType": "semver"
      }
    ],
    "programFiles": [
      "fs/smb/server/smbacl.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.0"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.0",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.157",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.110",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.52",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.6",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/smb/server/smbacl.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-90153

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#36545 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement

Revision history

  1. CVE-2026-90153 · Revision 1Source updated