CVE-2021-43351 was registered as a potential software vulnerability in late 2021. However, after review by the Common Vulnerabilities and Exposures (CVE) team, it was marked as REJECTED. This means the CVE entry was not used and does not describe a real or confirmed vulnerability.

Despite being unused, it still appears in some vulnerability trackers and can cause confusion when developers or security researchers come across it. In this post, we’ll explain what it means when a CVE is rejected, show how such confusion can happen, and why it's important to always verify CVE status.

Why Was CVE-2021-43351 Rejected?

On the official CVE database, the entry states:

> REJECT REASON: This is unused.

This means that while there might have been a report or reservation for this CVE, it was never assigned to a discovered vulnerability. There is no product, bug, or exploit code associated with it. Sometimes, entries like these are created in error or for bugs that turn out not to be security issues.

How Does This Affect Developers and Researchers?

You might encounter the CVE ID in tools, security scans, or automated reports. When searching for more information, you'll get little beyond the rejection notice. This can be confusing, especially if you’re checking for vulnerabilities in your software stack.

Example:

An automated scan might give you output like

{
  "id": "CVE-2021-43351",
  "description": "Reserved",
  "status": "Rejected",
  "severity": "Unknown"
}

If you dig into it, you’ll see there is, in fact, no risk — the CVE is essentially a placeholder that was never used.

Sample Python Script to Check CVE Status

Here's a quick Python snippet using the free cve-search API to check a CVE status and alert if it is REJECTED:

import requests

cve_id = "CVE-2021-43351"
url = f"https://cve.circl.lu/api/cve/{cve_id}";

response = requests.get(url)
data = response.json()

if 'summary' in data and "REJECT" in data['summary']:
    print(f"{cve_id} is REJECTED: {data['summary']}")
else:
    print(f"{cve_id} is valid: {data.get('summary', 'No summary available')}")

Output

CVE-2021-43351 is REJECTED: REJECT REASON: This is unused.

References

- Official CVE record for CVE-2021-43351
- NVD Entry - CVE-2021-43351
- CVE Record Status Guidelines
- cve-search GitHub project

Final Thoughts

As you can see, not every CVE ID describes a real vulnerability. CVE-2021-43351 is listed as REJECTED: This is unused, meaning there's nothing to worry about for this entry. Always check the official references before taking action based on CVE reports.

If you see CVE-2021-43351 in any vulnerability report or security scanner output, you can safely disregard it — it does not pose any threat to your systems or applications.

Timeline

Published on: 02/23/2024 21:15:10 UTC
Last modified on: 02/26/2025 06:33:50 UTC