Vulnerability-Lookup

FKIE_CVE-2026-31704

Vulnerability from fkie_nvd - Published: 2026-05-01 14:16 - Updated: 2026-05-06 20:46

Severity ?

5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: use check_add_overflow() to prevent u16 DACL size overflow set_posix_acl_entries_dacl() and set_ntacl_dacl() accumulate ACE sizes in u16 variables. When a file has many POSIX ACL entries, the accumulated size can wrap past 65535, causing the pointer arithmetic (char *)pndace + *size to land within already-written ACEs. Subsequent writes then overwrite earlier entries, and pndacl->size gets a truncated value. Use check_add_overflow() at each accumulation point to detect the wrap before it corrupts the buffer, consistent with existing check_mul_overflow() usage elsewhere in smbacl.c.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/299f962c0b02d048fb45d248b4da493d03f3175d	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/8d5729350b236896f51379588d9a690b7fafb8db	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/e1955a94b6f17f4b058afa955a6f187eb3ed7615	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7	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": "B1ABA9F0-A5C4-4CBE-92EC-33CA7D4F7634",
              "versionEndExcluding": "6.6.136",
              "versionStartIncluding": "5.15",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "D4ECA0DE-AFF5-4688-B219-4CA2336CA5B7",
              "versionEndExcluding": "6.12.84",
              "versionStartIncluding": "6.7",
              "vulnerable": true
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            {
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              "vulnerable": true
            }
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          "negate": false,
          "operator": "OR"
        }
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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: use check_add_overflow() to prevent u16 DACL size overflow\n\nset_posix_acl_entries_dacl() and set_ntacl_dacl() accumulate ACE sizes\nin u16 variables. When a file has many POSIX ACL entries, the\naccumulated size can wrap past 65535, causing the pointer arithmetic\n(char *)pndace + *size to land within already-written ACEs. Subsequent\nwrites then overwrite earlier entries, and pndacl-\u003esize gets a\ntruncated value.\n\nUse check_add_overflow() at each accumulation point to detect the\nwrap before it corrupts the buffer, consistent with existing\ncheck_mul_overflow() usage elsewhere in smbacl.c."
    }
  ],
  "id": "CVE-2026-31704",
  "lastModified": "2026-05-06T20:46:54.840",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-05-01T14:16:20.367",
  "references": [
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    },
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
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      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
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      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2026-31704 (GCVE-0-2026-31704)

Vulnerability from cvelistv5 – Published: 2026-05-01 13:56 – Updated: 2026-05-01 13:56

Title

ksmbd: use check_add_overflow() to prevent u16 DACL size overflow

Summary

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/8d5729350b236896f…
	https://git.kernel.org/stable/c/e1955a94b6f17f4b0…
	https://git.kernel.org/stable/c/5e7b8f3c539d69b2e…
	https://git.kernel.org/stable/c/ef7902be3f215b6bf…
	https://git.kernel.org/stable/c/299f962c0b02d048f…

Impacted products

Vendor

Product

Version

Linux

Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 8d5729350b236896f51379588d9a690b7fafb8db (git)
Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < e1955a94b6f17f4b058afa955a6f187eb3ed7615 (git)
Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43 (git)
Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7 (git)
Affected: e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 , < 299f962c0b02d048fb45d248b4da493d03f3175d (git)

Linux

Affected: 5.15
Unaffected: 0 , < 5.15 (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/server/smbacl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "versionType": "git"
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              "lessThan": "ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7",
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smbacl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
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            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "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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    "dateUpdated": "2026-05-01T13:56:03.243Z",
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  "dataVersion": "5.2"
}

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-2026-31704

CVE-2026-31704 (GCVE-0-2026-31704)

Tags

Sightings

Nomenclature