Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=718 There is a use-after-free in Sprite Creation. If a Sprite is created, and then the handler for the frameConstructed event triggers a remove object action, the Sprite is then used after it has been freed. A sample swf is attached. Proof of Concept: https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/39610.zip