Phlex XSS protection bypass via attribute splatting, dynamic tags, and href values

Impact During a security audit conducted with Claude Opus 4.6 and GPT-5.3-Codex, we identified three specific ways to bypass the XSS cross-site-scripting protection built into Phlex. 1. The first bypass could happen if user-provided attributes with string keys were splatted into HTML tag, e.g...