{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "bc3e9dd9d104ca1b75644eab87b38ce8a924aef4"
            },
            {
              "fixed": "fb736ab4fb8c4fdb8b2f9ccd3a62e03d11549ca1"
            },
            {
              "fixed": "7fa84c9ca690643f429ae2709584a47e74b572c9"
            },
            {
              "fixed": "2a9aee9ef5622d58d8aafaa3263b3ffe70e2d9dd"
            },
            {
              "fixed": "0ee150794c75bcd0be0e24ff3394f433cbae18cc"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.12.0"
            },
            {
              "fixed": "6.12.111"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.53"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97555.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix heap overflow in DACL owner/group rewrite\n\nWhen id_mode_to_cifs_acl rewrites an existing DACL, it allocates a\nbuffer sized according to the on-disk DACL length reported by\ndacl_ptr-\u003esize. However, replace_sids_and_copy_aces may rewrite each\nACE with a new owner/group SID obtained from the cifs.idmap upcall.\nThose SIDs can have up to SID_MAX_SUB_AUTHORITIES (15) sub-authorities,\nmaking each ACE up to 76 bytes (sizeof(struct smb_ace)).\n\nIf the original DACL contains short SIDs (e.g., 1 sub-authority) while\nthe replacement SIDs are long, the rewritten ACEs overflow the\nallocation.\n\nFix this by always budgeting for worst-case SID expansion: allocate\nsizeof(struct smb_acl) plus num_aces * sizeof(struct smb_ace), which\ncovers the smb_acl header and room for every ACE at maximum SID size.\nThis replaces the previous split logic that used dacl_ptr-\u003esize for\ncifsacl mounts but num_aces * sizeof(struct smb_ace) for mode_from_sid\nmounts: both paths can trigger the same rewrite and need the same\nheadroom.\n\nKASAN reports this as:\n  BUG: KASAN: slab-out-of-bounds in build_sec_desc+0x1e8a/0x2680 [cifs]\n  Write of size 4 at addr ffff8881a5e25374 by task chown/5298\n  ...\n  The buggy address is located 0 bytes to the right of\n   allocated 884-byte region [ffff8881a5e25000, ffff8881a5e25374)",
  "id": "CVE-2026-97555",
  "modified": "2026-09-27T03:30:28.065464589Z",
  "published": "2026-09-25T10:21:46.445Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0ee150794c75bcd0be0e24ff3394f433cbae18cc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2a9aee9ef5622d58d8aafaa3263b3ffe70e2d9dd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7fa84c9ca690643f429ae2709584a47e74b572c9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fb736ab4fb8c4fdb8b2f9ccd3a62e03d11549ca1"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97555.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-97555"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "smb: client: fix heap overflow in DACL owner/group rewrite"
}