Source summary
Aegisub is a cross-platform advanced subtitle editor. From 3.2.0 to 3.4.2, Aegisub automatically loads Automation scripts referenced by Automation Scripts metadata in ASS subtitle projects without asking whether the user trusts the scripts or their authors. An attacker can distribute a crafted ASS file together with a referenced malicious Automation script, and opening the AS file executes arbitrary code with the privileges of the Aegisub process. From 3.4.0 to 3.4.2, inconsistent handling of embedded NUL characters between extension validation and filesystem operations additionally allows a crafted ASS/Lua polyglot to reference and execute itself as a single-file variant. The vulnerability is fixed in Aegisub 3.5.0.