CVE-2026-63817
f2fs: validate compress cache inode only when enabled
In the Linux kernel, the following vulnerability has been resolved: f2fs: validate compress cache inode only when enabled F2FS_COMPRESS_INO() uses NM_I(sbi)->max_nid as the synthetic inode number for the compressed page cache inode. That inode only exists when the compress_cache mount option is enabled. When compress_cache is disabled, max_nid is outside the valid inode range. A corrupted directory entry that points to ino == max_nid should therefore be rejected by f2fs_check_nid_range(). However, is_meta_ino() currently treats F2FS_COMPRESS_INO() as a meta inode unconditionally, so f2fs_iget() bypasses do_read_inode() and its nid range check, and instantiates a fake internal inode instead. Gate the compressed cache inode case on COMPRESS_CACHE, matching f2fs_init_compress_inode(). With compress_cache disabled, ino == max_nid now follows the normal inode path and is rejected as an out-of-range nid.
| Vendor | linux |
| Product | linux |
| Ecosystems | |
| Industries | Technology |
| Published | Jul 19, 2026 |
| Last Updated | Aug 17, 2026 |
Get instant alerts for linux linux
Be the first to know when new high vulnerabilities affecting linux linux are published — delivered to Slack, Telegram or Discord.
CVSS v3 Breakdown
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H