Nuclei is a vulnerability scanner. Prior to version 2.9.9, a security issue in the Nuclei project affected users utilizing Nuclei as Go code (SDK) running custom templates. This issue did not affect CLI users. The problem was related to sanitization issues with payload loading in sandbox mode. There was a potential risk with payloads loading in sandbox mode. The issue occurred due to relative paths not being converted to absolute paths before doing the check for "sandbox" flag allowing arbitrary files to be read on the filesystem in certain cases when using Nuclei from "Go" SDK implementation. This issue has been fixed in version 2.9.9. The maintainers have also enabled sandbox by default for filesystem loading. This can be optionally disabled if required. The "-sandbox" option has been deprecated and is now divided into two new options: "-lfa" (allow local file access) which is enabled by default and "-lna" (restrict local network access) which can be enabled by users optionally. The "-lfa" allows file (payload) access anywhere on the system (disabling sandbox effectively), and "-lna" blocks connections to the local/private network.