It was well-known that PGP is vulnerable to short-ID collisions,
and many experiments were done to demonstrate that. 
Nevertheless, real attacks started in June, some developers found
their fake keys with same name, email, and even "same" fake signatures
by more fake keys in the wild, on the keyservers. 
All these keys have same short-IDs, created by collision attacks, led
with some discussions about the danger of short-IDs. Now, it is worth
to mention this issue again, since fake keys of Linus Torvalds, Greg Kroah-Hartman,
and other kernel devs are found in the wild recently.
> We don't know who is behind this, or what his purpose is. We just know this
> looks very evil.
Source: LKML: <1471274895@i2pmail …: Fake Linus Torvalds’ Key Found in the Wild, No More Short-IDs.