{"schema_version":"1.7.5","id":"CVE-2026-63815","published":"2026-07-19T12:02:15.345Z","modified":"2026-07-25T04:14:34.989797323Z","related":["openSUSE-SU-2026:11339-1"],"summary":"f2fs: bound i_inline_xattr_size for non-inline-xattr inodes","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->i_inline_xattr_size = le16_to_cpu(ri->i_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->max (int) to a negative\nvalue.  The inline directory walk then compares an unsigned long bit_pos\nagainst that negative d->max, which is promoted to a huge unsigned bound,\nand reads far past the inline area:\n\n\twhile (bit_pos < d->max)\t\t/* fs/f2fs/dir.c */\n\t\t... test_bit_le(bit_pos, d->bitmap) / d->dentry[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.","affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6afc662e68b5f988282ff20afd58a89b1c279dca"},{"fixed":"3c8d6b4093aea40a20596f452289e7c22d84e6d5"},{"fixed":"a08ee30dcbeff6b97df75c38c2589603ddde53a6"},{"fixed":"c3e05522daae4e7348a1ea81eeb321d25aa0fd3b"},{"fixed":"76e1a05cf6d4051931d7fa4ead51a05786a62918"},{"fixed":"2a9f9791653ba5ed3fb45bbffa8d63a7cd5cf706"},{"fixed":"4ce2d52f680c1d8bfdad7cce05b815ea7ca9790d"},{"fixed":"16bc237ce3c483b75575abea53cfb639745311ed"},{"fixed":"378acf3cf19b6af6cba55e8dd1154c4e1504bae8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63815.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","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"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63815.json"}}],"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"}],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63815.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}