Vulnerability-Lookup

FKIE_CVE-2026-43350

Vulnerability from fkie_nvd - Published: 2026-05-08 14:16 - Updated: 2026-05-15 19:29

Severity ?

7.6 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

Summary

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.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2757ad3e4b6f9e0fed4c7739594e702abc5cab21	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/38a69f08ee82c450d3e4168707fff2e317dc3ff7	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/b53b8e98c23310294fc45fc686db5ee860311896	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/c8eef12af1cc73031639ea7cf16e0b10e2536b0b	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/f8488c07bea2431ee12a6067d736578064fa46b4	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*

JSON

To clipboard

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "69577FD5-601B-4A4B-BBA2-0FC336EB0D3E",
              "versionEndExcluding": "6.6.136",
              "versionStartIncluding": "5.4",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "D4ECA0DE-AFF5-4688-B219-4CA2336CA5B7",
              "versionEndExcluding": "6.12.84",
              "versionStartIncluding": "6.7",
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: require a full NFS mode SID before reading mode bits\n\nparse_dacl() treats an ACE SID matching sid_unix_NFS_mode as an NFS\nmode SID and reads sid.sub_auth[2] to recover the mode bits.\n\nThat assumes the ACE carries three subauthorities, but compare_sids()\nonly compares min(a, b) subauthorities.  A malicious server can return\nan ACE with num_subauth = 2 and sub_auth[] = {88, 3}, which still\nmatches sid_unix_NFS_mode and then drives the sub_auth[2] read four\nbytes past the end of the ACE.\n\nRequire num_subauth \u003e= 3 before treating the ACE as an NFS mode SID.\nThis keeps the fix local to the special-SID mode path without changing\ncompare_sids() semantics for the rest of cifsacl."
    }
  ],
  "id": "CVE-2026-43350",
  "lastModified": "2026-05-15T19:29:35.360",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.6,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 4.7,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-05-08T14:16:45.123",
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    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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    },
    {
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    }
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2026-43350 (GCVE-0-2026-43350)

Vulnerability from cvelistv5 – Published: 2026-05-08 13:41 – Updated: 2026-05-11 22:22

Title

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

Summary

Severity ?

7.6 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

Assigner

Linux

References

5 references

URL	Tags
https://git.kernel.org/stable/c/b53b8e98c23310294…
https://git.kernel.org/stable/c/c8eef12af1cc73031…
https://git.kernel.org/stable/c/38a69f08ee82c450d…
https://git.kernel.org/stable/c/f8488c07bea2431ee…
https://git.kernel.org/stable/c/2757ad3e4b6f9e0fe…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: e2f8fbfb8d09c06decde162090fac3ee220aa280 , < b53b8e98c23310294fc45fc686db5ee860311896 (git) Affected: e2f8fbfb8d09c06decde162090fac3ee220aa280 , < c8eef12af1cc73031639ea7cf16e0b10e2536b0b (git) Affected: e2f8fbfb8d09c06decde162090fac3ee220aa280 , < 38a69f08ee82c450d3e4168707fff2e317dc3ff7 (git) Affected: e2f8fbfb8d09c06decde162090fac3ee220aa280 , < f8488c07bea2431ee12a6067d736578064fa46b4 (git) Affected: e2f8fbfb8d09c06decde162090fac3ee220aa280 , < 2757ad3e4b6f9e0fed4c7739594e702abc5cab21 (git)
Linux	Linux	Affected: 5.4 Unaffected: 0 , < 5.4 (semver) Unaffected: 6.6.136 , ≤ 6.6.* (semver) Unaffected: 6.12.84 , ≤ 6.12.* (semver) Unaffected: 6.18.25 , ≤ 6.18.* (semver) Unaffected: 7.0.2 , ≤ 7.0.* (semver) Unaffected: 7.1-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/client/cifsacl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "status": "affected",
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              "versionType": "git"
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              "versionType": "git"
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          ]
        },
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          "programFiles": [
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          ],
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          "vendor": "Linux",
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            {
              "status": "affected",
              "version": "5.4"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "version": "6.6.136",
              "versionType": "semver"
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              "version": "6.18.25",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "7.0.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1-rc1",
              "versionType": "original_commit_for_fix"
            }
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        }
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        {
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        }
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      "title": "smb: client: require a full NFS mode SID before reading mode bits",
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    "datePublished": "2026-05-08T13:41:53.276Z",
    "dateReserved": "2026-05-01T14:12:56.003Z",
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    "state": "PUBLISHED"
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

FKIE_CVE-2026-43350

CVE-2026-43350 (GCVE-0-2026-43350)

Tags

Sightings

Nomenclature