CVE

A CVE (Common Vulnerabilities and Exposures) identifier — like CVE-2021-44228 (Log4Shell) — is the industry-standard unique reference for a single publicly disclosed security flaw. Vendors, scanners, and threat feeds all key off CVE IDs so everyone is talking about the same bug. When a CVE is being actively exploited it usually lands on CISA's Known Exploited Vulnerabilities list, your cue to patch now.