Amazon has big contracts for hosting cloud infrastructure for the major intelligence & military agencies. presumably those aws contractors participated in project glasswing and had a list of vulnerabilities in software they use which they're working to patch. checking if those new undisclosed vulnerabilities are discoverable with fable is presumably part of the job and they'd report any findings upwards and to the govt as a matter of course, not specifically to screw over anthropic.
@spiral_archtct @PussyBlaster10k @hugolowell you can also see why no one involved can provide details of the vulnerability nor the potential impact of it being exploited lest the disclosure itself point malicious hackers towards a hole they could exploit before it's fixed.