{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "6afc662e68b5f988282ff20afd58a89b1c279dca"
            },
            {
              "fixed": "3c8d6b4093aea40a20596f452289e7c22d84e6d5"
            },
            {
              "fixed": "a08ee30dcbeff6b97df75c38c2589603ddde53a6"
            },
            {
              "fixed": "c3e05522daae4e7348a1ea81eeb321d25aa0fd3b"
            },
            {
              "fixed": "76e1a05cf6d4051931d7fa4ead51a05786a62918"
            },
            {
              "fixed": "2a9f9791653ba5ed3fb45bbffa8d63a7cd5cf706"
            },
            {
              "fixed": "4ce2d52f680c1d8bfdad7cce05b815ea7ca9790d"
            },
            {
              "fixed": "16bc237ce3c483b75575abea53cfb639745311ed"
            },
            {
              "fixed": "378acf3cf19b6af6cba55e8dd1154c4e1504bae8"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.15.0"
            },
            {
              "fixed": "5.10.261"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.212"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.178"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.145"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.96"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.39"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63815.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: bound i_inline_xattr_size for non-inline-xattr inodes\n\nWhen the flexible_inline_xattr feature is enabled, do_read_inode() loads\nthe on-disk i_inline_xattr_size unconditionally:\n\n\tif (f2fs_sb_has_flexible_inline_xattr(sbi))\n\t\tfi-\u003ei_inline_xattr_size = le16_to_cpu(ri-\u003ei_inline_xattr_size);\n\nbut sanity_check_inode() only range-checks it when the inode also has the\nFI_INLINE_XATTR flag set.  An inode that carries an inline dentry or inline\ndata but not FI_INLINE_XATTR -- the normal layout for an inline\ndirectory -- therefore keeps a fully attacker-controlled\ni_inline_xattr_size from a crafted image.\n\nget_inline_xattr_addrs() returns that value with no flag gating, so it\nfeeds the inode geometry:\n\n\tMAX_INLINE_DATA()  = 4 * (CUR_ADDRS_PER_INODE - i_inline_xattr_size - 1)\n\tNR_INLINE_DENTRY() = MAX_INLINE_DATA() * BITS_PER_BYTE / (...)\n\taddrs_per_page()   = CUR_ADDRS_PER_INODE - i_inline_xattr_size\n\nA large i_inline_xattr_size drives MAX_INLINE_DATA() and NR_INLINE_DENTRY()\nnegative, so make_dentry_ptr_inline() sets d-\u003emax (int) to a negative\nvalue.  The inline directory walk then compares an unsigned long bit_pos\nagainst that negative d-\u003emax, which is promoted to a huge unsigned bound,\nand reads far past the inline area:\n\n\twhile (bit_pos \u003c d-\u003emax)\t\t/* fs/f2fs/dir.c */\n\t\t... test_bit_le(bit_pos, d-\u003ebitmap) / d-\u003edentry[bit_pos] ...\n\nMounting a crafted image and reading such a directory triggers an\nout-of-bounds read in f2fs_fill_dentries(); the same underflow also\ncorrupts ADDRS_PER_INODE for regular files.\n\nValidate i_inline_xattr_size against MAX_INLINE_XATTR_SIZE whenever the\nflexible_inline_xattr feature is enabled -- i.e. whenever the value is\nloaded from disk and consumed -- and keep the lower MIN_INLINE_XATTR_SIZE\nbound gated on inodes that actually carry an inline xattr, so legitimate\ninodes with i_inline_xattr_size == 0 are still accepted.",
  "id": "CVE-2026-63815",
  "modified": "2026-08-18T03:31:17.406840946Z",
  "published": "2026-07-19T12:02:15.345Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/16bc237ce3c483b75575abea53cfb639745311ed"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2a9f9791653ba5ed3fb45bbffa8d63a7cd5cf706"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/378acf3cf19b6af6cba55e8dd1154c4e1504bae8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3c8d6b4093aea40a20596f452289e7c22d84e6d5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4ce2d52f680c1d8bfdad7cce05b815ea7ca9790d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/76e1a05cf6d4051931d7fa4ead51a05786a62918"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a08ee30dcbeff6b97df75c38c2589603ddde53a6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c3e05522daae4e7348a1ea81eeb321d25aa0fd3b"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63815.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63815"
    },
    {
      "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:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "f2fs: bound i_inline_xattr_size for non-inline-xattr inodes"
}