# GSD-2021-1000757: mm, hugetlb: fix simple resv_huge_pages underflow on UFFDIO_COPY

> A local attacker can trigger an integer underflow in the hugetlb subsystem via UFFDIO_COPY, potentially causing a denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 Jun 2021

## What is GSD-2021-1000757?

GSD-2021-1000757 is a vulnerability in Kernel, published on 25 Jun 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

mm, hugetlb: fix simple resv_huge_pages underflow on UFFDIO_COPY

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 v5.4.125 by commit 14fd3da3e8d3de7f34d69dd4bfa5fd9e73d99911, it was introduced in version v4.11 by commit 8fb5debc5fcd450470cdd789c2d80ef95ebb8cf4. For more details please see the references link.

## Which versions are affected by GSD-2021-1000757?

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-2021-1000757?

No fix has been published for GSD-2021-1000757 yet. Limit exposure of the affected software until one is available.

## Is GSD-2021-1000757 being exploited?

There is no known exploitation of GSD-2021-1000757 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GSD-2021-1000757 and fix it if it is affected.

What it is: GSD-2021-1000757 is a vulnerability in Kernel, published on 25 Jun 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-2021-1000757 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-2021-1000757/ (Markdown: https://insights.sbomify.com/GSD-2021-1000757/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GSD-2021-1000757

---
From sbomify Insights: https://insights.sbomify.com/GSD-2021-1000757/
Summaries are generated and may contain mistakes; the official description above is the record.