CVE-2025-71161 dm-verity: disable recursive forward error correction
A flaw in Linux kernel dm-verity allows attackers to cause denial of service via recursive forward error correction loops.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-71161?
CVE-2025-71161 is a high-severity denial of service vulnerability in Linux kernel, published on 23 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
dm-verity: disable recursive forward error correction
There are two problems with the recursive correction:
1. It may cause denial-of-service. In fec_read_bufs, there is a loop that has 253 iterations. For each iteration, we may call verity_hash_for_block recursively. There is a limit of 4 nested recursions - that means that there may be at most 253^4 (4 billion) iterations. Red Hat QE team actually created an image that pushes dm-verity to this limit - and this image just makes the udev-worker process get stuck in the 'D' state.
2. It doesn't work. In fec_read_bufs we store data into the variable "fio->bufs", but fio bufs is shared between recursive invocations, if "verity_hash_for_block" invoked correction recursively, it would overwrite partially filled fio->bufs.
Which versions are affected by CVE-2025-71161?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-71161?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-71161 being exploited?
There is no known exploitation of CVE-2025-71161 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-75129, AZL-78437, BELL-CVE-2025-71161, DEBIAN-CVE-2025-71161, GHSA-m3cp-9jq6-3gg3, ROOT-OS-DEBIAN-11-CVE-2025-71161 and 5 more.