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CVE-2021-20142: An unauthenticated command injection vulnerability exists in the parameters of operation 41 in the controller_

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HIGH 8.8UPGRADE

CVE-2021-20142 is a high-severity flaw (CVSS 8.8) affecting gryphon tower firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An unauthenticated command injection vulnerability exists in the parameters of operation 41 in the controller_server service on Gryphon Tower routers. An unauthenticated remote attacker on the same network can execute commands as root on the device by sending a specially crafted malicious packet to the controller_server service on port 9999.

Why this priority

  • High severity
  • Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score8.8 (High)
Attack vectorAdjacent network
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance3.7% (top 10%)
CISA exploited listNo
WeaknessCWE-78
Published2021-12-09
Last modified2026-06-17
Publisher (CNA): Tenable Network Security, Inc. · Vendor: gryphonconnect

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Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

gryphonconnect gryphon tower firmware UPGRADE
Affected: <= 04.0004.12
Fixed in: newer than 04.0004.12
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-20142?

gryphon tower firmware: upgrade to newer than 04.0004.12. Exact commands for each OS are on this page.

Is CVE-2021-20142 being exploited?

CVE-2021-20142 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-20142 affect?

CVE-2021-20142 affects gryphon tower firmware. Severity is high (CVSS 8.8). An unauthenticated command injection vulnerability exists in the parameters of operation 41 in the controller_server service on Gryphon Tower routers. An unauthenticated remote attacker on the same network can execute commands as root on th

How urgent is CVE-2021-20142?

Priority 58/100. High severity; Public exploit reference

Related CVEs

References

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