Several Emacs releases have violated the GPL by mistake:

It turns out that the Emacs 23.2 and 23.3 releases contain a number of parsers created with Bison, but the source for those parsers was not included. That has led Richard Stallman to say: “We have made a very bad mistake. Anyone redistributing those versions is violating the GPL, through no fault of his own. We need to fix those releases retroactively (or else delete them), and we need to do it right away.”

As far as violations go, this isn’t one that people should get exited over. There are many others that pose real problems:

And please, while we all see the snickering-inducing irony of FSF and its GNU project violating the GPL, keep in mind that this is what I’ve typically called a “community violation”. It’s a non-profit volunteer project that made an honest mistake and is resolving it quickly. Meanwhile, I’ve a list of hundreds of companies who are actively violating the GPL, ignoring users who requested source, and have apparently no interest in doing the right thing until I open an enforcement action against them. So, please keep perspective about what how bad any given violation is. Not all GPL violations are of equal gravity, but all should be resolved, of course. The Emacs developers are on it.

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Several Emacs releases have violated the GPL by mistake: It turns out that the Emacs 23.2 and 23.3 releases contain a number of parsers created with Bison, but the source for those parsers was not included. That has led Richard Stallman to say: "We have made a very bad mistake. Anyone redistributing those versions is ...