CVE-2024-42304: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: ext4: make sure the first directory block is not a hole The syzbot constructs a directory that has no dirblock but is non-inline, i.e. the first directory block is a hole. And no errors are reported when creating files in this directory in the following flow. ext4_mknod ... ext4_add_entry // Read block 0 ext4_read_dirblock(dir, block, DIRENT) bh = ext4_bread(NULL, inode, block, 0) if (!bh && (type == INDEX || type == DIRENT_HTREE)) // The first directory block is a hole // But type == DIRENT, so no error is reported. After that, we get a directory block without '.' and '..' but with a valid dentry. This may cause some code that relies on dot or dotdot (such as make_indexed_dir()) to crash. Therefore when ext4_read_dirblock() finds that the first directory block is a hole report that the filesystem is corrupted and return an error to avoid loading corrupted data from disk causing something bad.

Affected products

• Linux Linux Kernel: from 4.9.187, before 4.10 (fixed in 4.10); from 4.14.135, before 4.15 (fixed in 4.15); from 4.19.62, before 4.19.320 (fixed in 4.19.320); from 5.1.21, before 5.2 (fixed in 5.2); from 5.2.4, before 5.4.282 (fixed in 5.4.282); from 5.5, before 5.10.224 (fixed in 5.10.224); …

Published 2024-08-17. Last modified 2026-08-04.