Going by the podcast darknet diaries: Yes.
Them or the US or China
Edit: Around the RCE IPv6 bug in Windows, China threatend to block publishing of exploits. They required to first disclosing it with the government before a researcher is allowed to publish it.
I know that in the past Israel was the main provider for these exploits and spyware. Is it still the case?
Going by the podcast darknet diaries: Yes.
Them or the US or China
Edit: Around the RCE IPv6 bug in Windows, China threatend to block publishing of exploits. They required to first disclosing it with the government before a researcher is allowed to publish it.