The Linux kernel’s ext4 file system incorrectly publishes a jinode pointer before the underlying journal inode is fully initialized. A reader can observe a non‑NULL jinode while its corresponding VFS inode has no mapping, allowing the fast‑commit flush path to dereference an uninitialized pointer. This results in a kernel panic.

This issue exists in all Linux kernels that compile the vulnerable ext4 code before the patch that moved the jinode initialization to after jbd2_inode creation. The CPE list includes kernel 3.11, its release candidates rc6 and rc7, 7.0 RC1 through RC5, and the generic Linux kernel. In practice, any kernel version older than the commit that fixed the issue is affected. System administrators should verify their kernel release against the patch set.

This vulnerability has a CVSS score of 8.8 and an EPSS score of less than 1 %, indicating high severity but low probability of exploitation. It is not listed in the CISA KEV catalog. Attackers can trigger a kernel crash by performing a write, sync, or fsync operation on an ext4 mounted volume, causing denial of service for the entire system.