CVE-2021-33148 - What You Need to Know (and Why It’s Actually Not an Issue)

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Sometimes in cybersecurity, you come across a CVE (Common Vulnerabilities and Exposures) entry that creates a bit of confusion before everyone realizes the vulnerability isn’t even there. That’s exactly what happened with CVE-2021-33148. Despite some initial chatter about a possible exploit, this CVE was officially rejected with the reason: “This is unused.” Let’s break this down in simple terms, share the official sources, show what the code *might* have looked like (if there were one), and help you understand why this matters.

What Is CVE-2021-33148?

CVE-2021-33148 appeared like any other security tracking number, but if you check the official records, you’ll notice something unusual. The entry says:

> REJECT - This candidate has been rejected by its CNA. This is unused.
>
> (Source: CVE.org)

So, what does that mean? In plain English, a *CNA* is a *CVE Numbering Authority* –– a trusted organization that assigns and manages CVE numbers. Sometimes, these numbers are reserved early, in case a newly-found bug needs an entry. If, after a deeper check, the bug turns out not to exist, or the report is a mistake or duplicate, the entry is officially rejected and marked as “unused”.

What About Exploit or Vulnerable Code?

Normally, a CVE long read would show real or proof-of-concept exploit code. For CVE-2021-33148, though, no such example exists — because there’s no bug! But, to help you understand what a typical exploit snippet *might* look like for actual CVEs (not this one!), here’s a basic harmless example:

# Example: An exploit for a real buffer overflow might look like this
buffer = b"A" * 1024  # Sending too much data!
sock.send(buffer)

There are a few authoritative places where you can check the status of CVEs

- CVE.org’s official entry for CVE-2021-33148
- NVD (National Vulnerability Database) entry (also says “REJECTED”)
- MITRE CVE list

Each says, in effect: This entry is rejected and unused. No CVE. No exploit.

Mislabeled or duplicate CVEs are discovered and the extra numbers must be nixed.

Rejecting unused entries helps keep the database accurate and avoids false alarms. It’s better to have a rejected CVE than one that’s misleading.

Takeaway for You

1. Don’t panic about CVE-2021-33148. It’s “unused”—there’s no bug, exploit, or vulnerability.

Timeline

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