#2701 Decompilation of a simple frame script freezes the program if code deobfuscation is off

If you are looking for the decompiler itself, visit https://github.com/jindrapetrik/jpexs-decompiler

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List of issues

Author:

dimusLV

Date created: 04/18/2026, 5:46:53 pm

Type: bug

Visibility: Everybody

Assigned to:

Labels: AS1/2 Deobfuscation

State: opened Help

> What steps will reproduce the problem? Open the frame 85 script of sprite with chid 192 in the attached .swf > What is the expected output? What do you see instead? If opened with code deobfuscation off, this seemingly freezes the program. If opened with deobfuscation on, it takes a bit to decompile, but eventually succeeds. > What version of the product are you using? Is it "nightly build"? Which operating system do you have? I am using stable version 26.0.0 on Windows 10. > Please provide any additional information below. If the problem is related to a SWF file, attach it here, otherwise we can't help you. Additional, somewhat unrelated note: if you open the .swf with a Flash player and click on "Play Game", on a non-debug v32 Flash player it seems to work normally, but on a debug v32 Flash player the game crashes (the window disappears). Any idea why that might be the case?

pipetopipe_2rnamentEdition_2.swf (1,143 KiB)

JPEXS

04/28/2026, 7:35:06 pm

Well, this SWF file is heavily obfuscated. We do not guarantee that FFDec won't crash/freeze when you walk through the obfuscated file scripts without deobfuscation on. If you do not turn on the deobfuscation then you receive invalid code, even if it does not freeze, so it does not make sense to leave it turned off (on obfuscated files). I can take a look what makes FFDec freeze in this specific case, but there are surely many other obfuscation cases which make FFDec unstable (without using the deobfuscation feature). The obfuscated files sometimes do not work in debug flash player as debug flash player has more checks for SWF integrity than regular flash player.

State: new→opened

Randomno

04/28/2026, 9:44:10 pm

Use an older version of debug Flash Player. I've had the same behaviour with files obfuscated in this way, v23 or newer will crash with Warning: Failed to parse corrupt data.