Cursor explicitly claims "Before an extension is shown in search or served as a download, Cursor runs automated malware and supply-chain analysis using commercial security tooling. Extensions that fail review are blocked. Cursor also monitors extension-ecosystem threat intelligence and updates its blocklist over time."
However, the bad extension was live for ~11 hours.
That's a testament to the strength of their so called "commercial quality" security tooling.
Norton Anti Virus...