A real prompt-injection case — and the blind spot it exposed in my own scanner (opens in new tab)

There's a documented real-world case worth learning from: in 2025, researchers at Legit Security showed GitLab Duo could be steered by instructions hidden inside ordinary project content. Part of what made it work was concealment — payloads obscured with tricks like Unicode smuggling and Base16 encoding so they wouldn't be obvious to a human or a naive text filter. GitLab patched it (tracked as duo-ui!52). I bring it up because it lines up with a blind spot I just documented in my own scanner...