[fenom/fenom] Sandbox bypass in fenom

In fenom 2.12.1 and before, there is a way in fenom/src/Fenom/Template.php function getTemplateCode()to bypass sandbox to execute arbitrary PHP code when disable_native_funcs is true.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-46433
• https://github.com/fenom-template/fenom/issues/331
• https://github.com/advisories/GHSA-674v-3g2w-84gx