# CVE-2021-42006: Memory corruption in n/a

> An out-of-bounds access in GCLib allows attackers to cause a segmentation fault via a crafted GFF file.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 4 Oct 2021
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2021-42006, GHSA-936f-wf9f-83xm, UBUNTU-CVE-2021-42006

## What is CVE-2021-42006?

CVE-2021-42006 is a high-severity memory corruption vulnerability in n/a, published on 4 Oct 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

An out-of-bounds access in GffLine::GffLine in gff.cpp in GCLib 0.12.7 allows an attacker to cause a segmentation fault or possibly have unspecified other impact via a crafted GFF file.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2021-42006?

It affects 1 product.


Products: Gclib Project Gclib.

## How do I fix CVE-2021-42006?

Upgrade to a fixed version.

## Is CVE-2021-42006 being exploited?

There is no known exploitation of CVE-2021-42006 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-42006 and fix it if it is affected.

What it is: CVE-2021-42006 is a high-severity memory corruption vulnerability in n/a, published on 4 Oct 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-42006 in the wild and no public exploit code.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

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/CVE-2021-42006/ (Markdown: https://insights.sbomify.com/CVE-2021-42006/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-42006
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-42006
- OSV: https://osv.dev/vulnerability/CVE-2021-42006

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-42006/
Summaries are generated and may contain mistakes; the official description above is the record.