CVE-2025-71161

A denial-of-service vulnerability was found in the Linux kernel's dm-verity device mapper target. The recursive forward error correction (FEC) implementation allows up to 253^4 (approximately 4 billion) iterations due to nested recursion in fec_read_bufs() and verity_hash_for_block(). A specially crafted dm-verity image can trigger this worst-case behavior, causing the udev-worker process to become stuck in uninterruptible sleep state.

This vulnerability was discovered by the Red Hat QE team who created a dm-verity image that triggers the maximum recursion depth. The resulting denial of service causes system processes to hang in D state, affecting system responsiveness. Additionally, the recursive FEC is fundamentally broken as the shared fio->bufs buffer gets overwritten during recursion. Local access to create or mount dm-verity images is required.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.