{
  "schema_version": "1.4.0",
  "id": "GHSA-3c4w-p6cr-wgq6",
  "modified": "2025-04-29T21:31:31Z",
  "published": "2024-05-21T15:31:39Z",
  "aliases": [
    "CVE-2021-47221"
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/slub: actually fix freelist pointer vs redzoning\n\nIt turns out that SLUB redzoning (\"slub_debug=Z\") checks from\ns->object_size rather than from s->inuse (which is normally bumped to\nmake room for the freelist pointer), so a cache created with an object\nsize less than 24 would have the freelist pointer written beyond\ns->object_size, causing the redzone to be corrupted by the freelist\npointer.  This was very visible with \"slub_debug=ZF\":\n\n  BUG test (Tainted: G    B            ): Right Redzone overwritten\n  -----------------------------------------------------------------------------\n\n  INFO: 0xffff957ead1c05de-0xffff957ead1c05df @offset=1502. First byte 0x1a instead of 0xbb\n  INFO: Slab 0xffffef3950b47000 objects=170 used=170 fp=0x0000000000000000 flags=0x8000000000000200\n  INFO: Object 0xffff957ead1c05d8 @offset=1496 fp=0xffff957ead1c0620\n\n  Redzone  (____ptrval____): bb bb bb bb bb bb bb bb               ........\n  Object   (____ptrval____): 00 00 00 00 00 f6 f4 a5               ........\n  Redzone  (____ptrval____): 40 1d e8 1a aa                        @....\n  Padding  (____ptrval____): 00 00 00 00 00 00 00 00               ........\n\nAdjust the offset to stay within s->object_size.\n\n(Note that no caches of in this size range are known to exist in the\nkernel currently.)",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
    }
  ],
  "affected": [],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47221"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ce6e8bee7a3883e8008b30f5887dbb426aac6a35"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e41a49fadbc80b60b48d3c095d9e2ee7ef7c9a8e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f6ed2357541612a13a5841b3af4dc32ed984a25f"
    }
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-763"
    ],
    "severity": "MODERATE",
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-05-21T15:15:11Z"
  }
}