CVE-2025-71161: dm-verity: disable recursive forward error correction
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 fecreadbufs, there is a loop that has 253 iterations. For each iteration, we may call verityhashforblock 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 fecreadbufs we store data into the variable "fio->bufs", but fio bufs is shared between recursive invocations, if "verityhashforblock" invoked correction recursively, it would overwrite partially filled fio->bufs.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Disable dm-verity recursive forward error correction (the material states: "dm-verity: disable recursive forward error correction").
dm-verity disable recursive forward error correction = enabled
Event History
Frequently Asked Questions
What is the severity of CVE-2025-71161?
CVE-2025-71161 is classified as a medium severity vulnerability due to its potential to cause denial-of-service issues.
How do I fix CVE-2025-71161?
To fix CVE-2025-71161, update your Linux kernel to the latest version where the vulnerability has been patched.
What systems are affected by CVE-2025-71161?
CVE-2025-71161 affects the Linux kernel, specifically systems utilizing dm-verity with recursive forward error correction enabled.
What is the impact of CVE-2025-71161?
The impact of CVE-2025-71161 may lead to a denial-of-service condition in systems using the affected kernel functionality.
When was CVE-2025-71161 disclosed?
CVE-2025-71161 was disclosed in 2025 as part of ongoing security assessments of the Linux kernel.