When browsing cybersecurity databases, you may come across CVE entries like CVE-2021-33160. Some researchers get curious when they see these identifiers, expecting details about a dangerous exploit or critical software bug. But not all CVEs are created equal—some, like CVE-2021-33160, are marked as "REJECTED" with a clear reason: "This is unused."

What is CVE-2021-33160?

CVE stands for Common Vulnerabilities and Exposures. It's the standard for identifying publicly known cybersecurity vulnerabilities. Every year, thousands of CVEs are logged to help track and share information about potential threats.

But CVE-2021-33160 is a little different. Here’s its official entry

CVE-2021-33160 (REJECT)
Reason: This is unused.

There is no code, exploit, or description provided. The entry is essentially a placeholder that’s been officially marked as irrelevant.

Why Would a CVE Be Rejected?

When vulnerabilities are reported or discovered, cybersecurity coordinators at MITRE (the administrator of the CVE list) assign them a CVE number. Sometimes things change:

The issue was not about exploitable code, or it was an internal tracking mistake.

For CVE-2021-33160, the reason is explicitly: "This is unused." This typically means the number was reserved but never associated with a real vulnerability.

What "Unused" Means for Security Professionals

So, what should you do if CVE-2021-33160 pops up in a scan or audit?

Nothing—and that's important. Sometimes, security scans or vulnerability management tools might pull up rejected or unused CVEs. You can safely ignore this entry, as it represents nothing that could endanger your system.

For example, if you filter a scan report for "critical" vulnerabilities and see CVE-2021-33160, you can mark it as a "false positive” or “not applicable."

If you want to see the official listing and verify this status, check these trusted sources

- NIST National Vulnerability Database (NVD): CVE-2021-33160
- MITRE CVE List: CVE-2021-33160

Sometimes it's helpful to recognize how "unused" CVEs could turn up in automated reports

def is_cve_rejected(cve_id):
    # Example check using pseudo-data
    rejected_cves = ["CVE-2021-33160", "CVE-202-XXXXX"]  # List from a CVE database
    return cve_id in rejected_cves

# Sample usage:
cve = "CVE-2021-33160"
if is_cve_rejected(cve):
    print(f"{cve} is rejected and unused. No action needed.")
else:
    print(f"{cve} may require review.")

Exploit Details

There are no exploit details for CVE-2021-33160.
No code, no proof-of-concept, nothing!

Quick FAQ

Q: Should I worry if my system or software lists CVE-2021-33160 as a vulnerability?
A: Nope! It's safe to mark it as irrelevant.

Q: Can I find more technical details about this CVE?
A: No, because it was never used for any real vulnerability.

Q: Why does it still show up in some scanners?
A: Some tools automatically download full CVE lists, including rejected entries.

Final Thoughts

CVE-2021-33160 is a good reminder that not every CVE entry represents a real-world threat. As a cybersecurity practitioner or developer, always double-check the official status of a CVE—when you see "REJECT" and "This is unused," there's *nothing* to worry about.

References

- NVD Entry for CVE-2021-33160
- MITRE Listing

*Share this post with your IT team so everyone’s on the same page about rejected CVEs!*

Timeline

Published on: 01/01/1976 00:00:00 UTC
Last modified on: 09/04/2025 00:40:36 UTC