NetBox versions 4.3.5 through 4.5.4 contain a remote code execution vulnerability in the RenderTemplateMixin.get_environment_params() method. Authenticated users with exporttemplate or configtemplate permissions can execute arbitrary code by specifying malicious Python callables in the environment_params field. The vulnerability allows attackers to bypass Jinja2 SandboxedEnvironment protections by setting the finalize parameter to importable Python callables like subprocess.getoutput. This bypass occurs outside the sandbox's call interception mechanism, enabling remote code execution as the NetBox service user.