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smb: client: require a full NFS mode SID before reading mode bits

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: smb: client: require a full NFS mode SID before reading mode bits parse_dacl() treats an ACE SID matching sid_unix_NFS_mode as an NFS mode SID and reads sid.sub_auth[2] to recover the mode bits. That assumes the ACE carries three subauthorities, but compare_sids() only compares min(a, b) subauthorities. A malicious server can return an ACE with num_subauth = 2 and sub_auth[] = {88, 3}, which still matches sid_unix_NFS_mode and then drives the sub_auth[2] read four bytes past the end of the ACE. Require num_subauth >= 3 before treating the ACE as an NFS mode SID. This keeps the fix local to the special-SID mode path without changing compare_sids() semantics for the rest of cifsacl.

Announced Source revision 1
Original source ↗

CVE-2026-43350

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-2026-43350

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": "e2f8fbfb8d09c06decde162090fac3ee220aa280",
        "lessThan": "23b54d6cc3ef30a51d984dc74364f24039ae2ecb",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e2f8fbfb8d09c06decde162090fac3ee220aa280",
        "lessThan": "1592a6cd6f653f2d24572a6976c7a775b19f4940",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e2f8fbfb8d09c06decde162090fac3ee220aa280",
        "lessThan": "8bd4cad3f458d11650d51c2d24b03fb1770ae6cc",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e2f8fbfb8d09c06decde162090fac3ee220aa280",
        "lessThan": "b53b8e98c23310294fc45fc686db5ee860311896",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e2f8fbfb8d09c06decde162090fac3ee220aa280",
        "lessThan": "c8eef12af1cc73031639ea7cf16e0b10e2536b0b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e2f8fbfb8d09c06decde162090fac3ee220aa280",
        "lessThan": "38a69f08ee82c450d3e4168707fff2e317dc3ff7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e2f8fbfb8d09c06decde162090fac3ee220aa280",
        "lessThan": "f8488c07bea2431ee12a6067d736578064fa46b4",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "e2f8fbfb8d09c06decde162090fac3ee220aa280",
        "lessThan": "2757ad3e4b6f9e0fed4c7739594e702abc5cab21",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/smb/client/cifsacl.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.4"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.4",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.259",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.210",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.175",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.136",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.84",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.25",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.0.2",
        "versionType": "semver",
        "lessThanOrEqual": "7.0.*"
      },
      {
        "status": "unaffected",
        "version": "7.1",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/smb/client/cifsacl.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-43350

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#40063 · Revision 1
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Publisher date
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