The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has been “silently” updating its Known Exploited Vulnerabilities (KEV) catalog when it concludes that vulnerabilities have been exploited by ransomware groups, according to a security researcher.

CISA adds a “known” or “unknown” field next to the “Known To Be Used in Ransomware Campaigns?” entry in its KEV catalog. The problem, according to a blog post by Glenn Thorpe of GreyNoise, is the agency doesn’t send out advisories when a vulnerability changes from “unknown” to “known” vulnerabilities exploited by ransomware groups.

Thorpe downloaded daily CISA KEV snapshots for all of 2025 and found that the agency had flipped 59 vul...