This would be the first report of such an issue that I’ve seen. But yes, it is technically possible for a malicious developer to put bad code in a plugin. Plugins are reviewed initially, but not constantly. This is why that “Turn off Safe Mode?” prompt when you first enable community plugins is so important.
To read more about plugin security, the following thread is a pretty good overview. (Note that this forum offers a summarizing feature, just under the first post in a busy thread.)
As for your situation, please report back. Most likely this is just a bug (at least, it doesn’t look like a malware warning to me—just a JavaScript error). And let us know what plugins you are using.
PS: have you installed any plugins manually, or just from the Community Plugins gallery?