# GSD-2021-1000138: ext4: fix check to prevent false positive report of incorrect used inodes

> A flaw in the ext4 filesystem allows local attackers to trigger a false positive error report, potentially causing a denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 31 May 2021

## What is GSD-2021-1000138?

GSD-2021-1000138 is a denial of service vulnerability in Kernel, published on 31 May 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

ext4: fix check to prevent false positive report of incorrect used inodes

This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven.
This ID is fixed in Linux Kernel version v5.10.36 by commit 098b257563b959f4ca6c1d82fde0ee727792cb19, it was introduced in version v4.18 by commit 5012284700775a4e6e3fbe7eac4c543c4874b559. For more details please see the references link.

## Which versions are affected by GSD-2021-1000138?

1 open source package ship an affected version, including Kernel.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Kernel` | Linux | All versions | None |

## How do I fix GSD-2021-1000138?

No fix has been published for GSD-2021-1000138 yet. Limit exposure of the affected software until one is available.

## Is GSD-2021-1000138 being exploited?

There is no known exploitation of GSD-2021-1000138 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GSD-2021-1000138 and fix it if it is affected.

What it is: GSD-2021-1000138 is a denial of service vulnerability in Kernel, published on 31 May 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of GSD-2021-1000138 in the wild and no public exploit code.

Affected packages and fixed versions:
- Kernel (Linux): affected all versions; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/GSD-2021-1000138/ (Markdown: https://insights.sbomify.com/GSD-2021-1000138/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GSD-2021-1000138

---
From sbomify Insights: https://insights.sbomify.com/GSD-2021-1000138/
Summaries are generated and may contain mistakes; the official description above is the record.