TN-5900 Series firmware versions v3.3 and prior are vulnerable to command-injection vulnerability. This vulnerability stems from insufficient input validation and improper authentication in the key-generation function, which could potentially allow malicious users to execute remote code on affected devices. 

References

• https://nvd.nist.gov/vuln/detail/CVE-2023-34213
• https://www.moxa.com/en/support/product-support/security-advisory/mpsa-230402-tn-5900-and-tn-4900-series-web-server-multiple-vulnerabilities