CVE-2026-99110

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix heap overflow in cifs_do_set_acl() cifs_set_acl() validates ACL size using posix_acl_xattr_size(): 4 + (count * 8) // 4-byte header + 8 bytes per ACE cifs_do_set_acl() then calls posix_acl_to_cifs() to write the CIFS wire format into the same buffer: 6 + (count * 10) // 6-byte header + 10 bytes per ACE An ACL that passes the xattr-based check in cifs_set_acl() can overflow the heap when posix_acl_to_cifs() writes the larger CIFS format. Validate the CIFS format size against the remaining buffer space and USHRT_MAX before converting--data_count is __u16, so sizes above USHRT_MAX truncate the on-wire packet length, causing the server to apply a partial ACL. Replace MaxDataCount = 1000 with min(CIFSMaxBufSize, USHRT_MAX).

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

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

Published

2026-10-28 11:17:30.410000

Last modified

2026-10-30 13:21:45.537000

View original CVE JSON

{
  "id": "CVE-2026-99110",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-10-28T11:17:30.410",
  "lastModified": "2026-10-30T13:21:45.537",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix heap overflow in cifs_do_set_acl()\n\ncifs_set_acl() validates ACL size using posix_acl_xattr_size():\n\n        4 + (count * 8)  // 4-byte header + 8 bytes per ACE\n\ncifs_do_set_acl() then calls posix_acl_to_cifs() to write the CIFS\nwire format into the same buffer:\n\n        6 + (count * 10)  // 6-byte header + 10 bytes per ACE\n\nAn ACL that passes the xattr-based check in cifs_set_acl() can\noverflow the heap when posix_acl_to_cifs() writes the larger CIFS\nformat.\n\nValidate the CIFS format size against the remaining buffer space and\nUSHRT_MAX before converting--data_count is __u16, so sizes above\nUSHRT_MAX truncate the on-wire packet length, causing the server to\napply a partial ACL.  Replace MaxDataCount = 1000 with\nmin(CIFSMaxBufSize, USHRT_MAX)."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "fs/smb/client/cifssmb.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66",
              "lessThan": "68652afb9b9adf70125971abee9b95341e042249",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66",
              "lessThan": "9312a00215602ba028495ef3fa00fb84af0478e0",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66",
              "lessThan": "d96f3365ce61c5f39602955af43c8174548dee98",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66",
              "lessThan": "596b4062e6c75bdd85a7f2b7f2087a872dc420ac",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66",
              "lessThan": "1dac61e2c29d1a71784604b48cf3b1234a65ec29",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "fs/smb/client/cifssmb.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.2",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.2",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.161",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.115",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.59",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.13",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1dac61e2c29d1a71784604b48cf3b1234a65ec29",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/596b4062e6c75bdd85a7f2b7f2087a872dc420ac",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/68652afb9b9adf70125971abee9b95341e042249",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9312a00215602ba028495ef3fa00fb84af0478e0",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d96f3365ce61c5f39602955af43c8174548dee98",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}