[3.4] bpo-32072: Fix issues with binary plists. (GH-4455) by serhiy-storchaka · Pull Request #4658 · python/cpython

I didn't expect that anyone would use plist files like this, they are a crummy interchange format. Sigh...

I'm not entirely convinced about the DDOS potential, the recursion should be stopped before the interpreter crashes and anyone reading nested data structures should already deal with unwanted recursion: I could just as easily send a plist file that contains a deeply nested list. An uncompressed XML plist file containing a array nested 1200 deep is still only about 18K bytes long, and should easily nest deep enough to hit the recursion limit.