If you have browsed security trackers or scanned your favorite software for CVEs, chances are you've stumbled across CVE-2021-33140. At first glance, it seems like just another identifier in the ocean of possible threats. You might have wondered, "Is this something I should fix? Is there any actual danger?"

The answer, surprisingly, is simple: CVE-2021-33140 was not used. It was rejected. But what exactly does a "rejected" or "unused" CVE mean, and why does this matter for developers and security professionals? Let's break down the history, what you’ll find if you search, sample code (and why there isn’t any), and the official references.

What Even Is CVE-2021-33140?

The Common Vulnerabilities and Exposures (CVE) System assigns IDs to publicly known cybersecurity vulnerabilities. CVE-2021-33140 is one of those IDs, but with a twist: it’s not connected to any vulnerability. This can happen for a variety of reasons, such as:

There was a clerical error

When that occurs, the CVE entry is officially rejected to make sure nobody wastes time worrying about a non-issue.

The official MITRE CVE listing for CVE-2021-33140 spells it out in a single short sentence:

> REJECT
> - Reason: This candidate was withdrawn by its CNA. Further investigation showed that it was not a vulnerability.

So, Is There Any Risk?

No. Because the vulnerability was never real. There’s no risk, patch, exploit, or workaround necessary.

Sample Non-Existent Exploit

Some people, when searching for public proof-of-concept code or Metasploit modules, might expect to find something like this:

# Exploit code for CVE-2021-33140 (This is just a placeholder)
print("There is no exploit for CVE-2021-33140 because it was rejected as unused.")

But in reality, no such code exists—and if you do find someone offering an “exploit” for CVE-2021-33140, beware: it might be misleading, malicious, or a scam.

Here are the most reliable places to look up the status of CVE-2021-33140

- MITRE's CVE Listing
- NVD Entry (also marked as rejected/unused)

> “This CVE ID has been rejected or withdrawn by its CVE Numbering Authority. No further information is available.”

Why Do Rejected CVEs Matter?

Rejected CVEs can crop up in vulnerability scanners, automated reports, and compliance documents. As a maintainer or IT pro, here’s what to do:

Don’t panic. Not every CVE is a real issue.

- Check official sources. They will confirm which CVEs are real, which are rejected, and which are fixes pending.
- Update documentation. Mark CVE-2021-33140 as not applicable so your colleagues don’t get confused.

Conclusion

CVE-2021-33140 is a classic case of a CVE that was created, reviewed, and then found *not* to be a real or relevant vulnerability. It’s a reminder that not every scary-looking code in your scan report deserves concern. The best habit? Always double-check with the official CVE and NVD pages before spending energy tracking down a non-existent bug.

*In short: CVE-2021-33140 was rejected. This is unused. You’re safe to move on!*

Timeline

Published on: 02/23/2024 21:15:09 UTC
Last modified on: 09/04/2025 00:40:35 UTC