f2fs: bound i_inline_xattr_size for non-inline-xattr inodes

{
  "id": "1741540af135a1bba48a3f42cd4b2d908f478fa2e34f36037522930335d5024f",
  "url": "https://osv.dev/vulnerability/CVE-2026-63815",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "f2fs: bound i_inline_xattr_size for non-inline-xattr inodes",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: f2fs: bound i_inline_xattr_size for non-inline-xattr inodes When the flexible_inline_xattr feature is enabled, do_read_inode() loads the on-disk i_inline_xattr_size unconditionally: if (f2fs_sb_has_flexible_inline_xattr(sbi)) fi->i_inline_xattr_size = le16_to_cpu(ri->i_inline_xattr_size); but sanity_check_inode() only range-checks it when the inode also has the FI_INLINE_XATTR flag set. An inode that carries an inline dentry or inline data but not FI_INLINE_XATTR -- the normal layout for an inline directory -- therefore keeps a fully attacker-controlled i_inline_xattr_size from a crafted image. get_inline_xattr_addrs() returns that value with no flag gating, so it feeds the inode geometry: MAX_INLINE_DATA() = 4 * (CUR_ADDRS_PER_INODE - i_inline_xattr_size - 1) NR_INLINE_DENTRY() = MAX_INLINE_DATA() * BITS_PER_BYTE / (...) addrs_per_page() = CUR_ADDRS_PER_INODE - i_inline_xattr_size A large i_inline_xattr_size drives MAX_INLINE_DATA() and NR_INLINE_DENTRY() negative, so make_dentry_ptr_inline() sets d->max (int) to a negative value. The inline directory walk then compares an unsigned long bit_pos against that negative d->max, which is promoted to a huge unsigned bound, and reads far past the inline area: while (bit_pos < d->max) /* fs/f2fs/dir.c */ ... test_bit_le(bit_pos, d->bitmap) / d->dentry[bit_pos] ... Mounting a crafted image and reading such a directory triggers an out-of-bounds read in f2fs_fill_dentr",
    "evidence": "osv:CVE-2026-63815",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.261",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.212",
            "evidence": "/affected/1/ranges"
          },
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            "value": "6.1.178",
            "evidence": "/affected/1/ranges"
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            "evidence": "/affected/1/ranges"
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            "evidence": "/affected/1/ranges"
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          {
            "value": "7.1.3",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-63815",
      "aliases": [
        "CVE-2026-63815"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
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                {
                  "fixed": "a08ee30dcbeff6b97df75c38c2589603ddde53a6"
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                {
                  "fixed": "c3e05522daae4e7348a1ea81eeb321d25aa0fd3b"
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            "ecosystem": "Linux"
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      "modified": "2026-10-28T02:30:39.167107078Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/16bc237ce3c483b75575abea53cfb639745311ed",
        "https://git.kernel.org/stable/c/2a9f9791653ba5ed3fb45bbffa8d63a7cd5cf706",
        "https://git.kernel.org/stable/c/378acf3cf19b6af6cba55e8dd1154c4e1504bae8",
        "https://git.kernel.org/stable/c/3c8d6b4093aea40a20596f452289e7c22d84e6d5",
        "https://git.kernel.org/stable/c/4ce2d52f680c1d8bfdad7cce05b815ea7ca9790d",
        "https://git.kernel.org/stable/c/76e1a05cf6d4051931d7fa4ead51a05786a62918",
        "https://git.kernel.org/stable/c/a08ee30dcbeff6b97df75c38c2589603ddde53a6",
        "https://git.kernel.org/stable/c/c3e05522daae4e7348a1ea81eeb321d25aa0fd3b",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63815.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-63815",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63815.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-63815",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 506785,
  "published_at": "2026-07-19T12:02:15.345+00:00"
}