PatchTheCVECVE-2021-20139: An unauthenticated command injection vulnerability exists in the parameters of operation 3 in the controller_s
CVE-2021-20139 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 3 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
- EPSS top 10%: very likely to be exploited
- Public exploit reference
A fixed release or distro patch exists.
Risk facts
| CVSS score | 8.8 (High) |
| Attack vector | Adjacent network |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 4.0% (top 10%) |
| CISA exploited list | No |
| Weakness | CWE-78 |
| Published | 2021-12-09 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
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-2021-20139?
gryphon tower firmware: upgrade to newer than 04.0004.12. Exact commands for each OS are on this page.
Is CVE-2021-20139 being exploited?
CVE-2021-20139 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-2021-20139 affect?
CVE-2021-20139 affects gryphon tower firmware. Severity is high (CVSS 8.8). An unauthenticated command injection vulnerability exists in the parameters of operation 3 in the controller_server service on Gryphon Tower routers. An unauthenticated remote attacker on the same network can execute commands as root on the
How urgent is CVE-2021-20139?
Priority 58/100. High severity; EPSS top 10%: very likely to be exploited; Public exploit reference
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