CVE-2026-72382

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: reject undersized DACLs before parsing ACEs parse_dacl() limits the attacker-controlled ACE count by comparing it with the number of minimal ACEs that fit in the DACL size. The DACL size field is 16 bits, but the expression subtracts sizeof(struct smb_acl). Because sizeof() is unsigned, a DACL size smaller than the ACL header underflows to a large size_t. A malicious client can reach this with: SMB2_SET_INFO (InfoType=SMB2_O_INFO_SECURITY) -> smb2_set_info_sec() -> set_info_sec() -> parse_sec_desc() -> parse_dacl() -> init_acl_state(..., 0xffff) -> init_acl_state(..., 0xffff) -> kmalloc_objs(..., 0xffff) Thus a malformed security descriptor can make num_aces pass the guard and drive large temporary ACL state and pointer-array allocations. Reject DACLs smaller than struct smb_acl before doing the subtraction, so the ACE count check cannot be bypassed by the underflow.

Severity

HIGH

CVSS score

8.8 (v3.1)

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-08-15 06:22:11.707000

Last modified

2026-10-30 13:19:50.623000

View original CVE JSON

{
  "id": "CVE-2026-72382",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-08-15T06:22:11.707",
  "lastModified": "2026-10-30T13:19:50.623",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: reject undersized DACLs before parsing ACEs\n\nparse_dacl() limits the attacker-controlled ACE count by comparing it\nwith the number of minimal ACEs that fit in the DACL size. The DACL size\nfield is 16 bits, but the expression subtracts sizeof(struct smb_acl).\nBecause sizeof() is unsigned, a DACL size smaller than the ACL header\nunderflows to a large size_t.\n\nA malicious client can reach this with:\n\nSMB2_SET_INFO (InfoType=SMB2_O_INFO_SECURITY)\n  -> smb2_set_info_sec()\n  -> set_info_sec()\n  -> parse_sec_desc()\n  -> parse_dacl()\n     -> init_acl_state(..., 0xffff)\n     -> init_acl_state(..., 0xffff)\n     -> kmalloc_objs(..., 0xffff)\n\nThus a malformed security descriptor can make num_aces pass the guard\nand drive large temporary ACL state and pointer-array allocations.\n\nReject DACLs smaller than struct smb_acl before doing the subtraction,\nso the ACE count check cannot be bypassed by the underflow."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "fs/smb/server/smbacl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "lessThan": "8dc949061e35427433feac3ebe5ec089f2aa857e",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "lessThan": "16fb65ec15fe7c90f50a2115854bfd9a032d4023",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "lessThan": "282847c0cf22f2e961155ac8e42f6eeab7e16049",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "lessThan": "d020e7f27bf65eecd3805404702f716b2b6d9e73",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "lessThan": "15a9e9b8f7f5d7f380ae54c6f5bcbc0bdcb0f3cd",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "lessThan": "60908f7ebcd9b6cde74ad5711fab0f49c7970949",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "fs/smb/server/smbacl.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "5.15",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "5.15",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.191",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.145",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.97",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.40",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.1.5",
              "lessThanOrEqual": "7.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9
      }
    ]
  },
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/15a9e9b8f7f5d7f380ae54c6f5bcbc0bdcb0f3cd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/16fb65ec15fe7c90f50a2115854bfd9a032d4023",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/282847c0cf22f2e961155ac8e42f6eeab7e16049",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/60908f7ebcd9b6cde74ad5711fab0f49c7970949",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8dc949061e35427433feac3ebe5ec089f2aa857e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d020e7f27bf65eecd3805404702f716b2b6d9e73",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}