Exploitation attempts against critical Atlassian flaw have begun (CVE-2026-21589)

One day after Atlassian released patches fixing a critical arbitrary file access vulnerability (CVE-2026-21589) in its self-managed Data Center products, and a few hours after watchTowr researchers published a technical rundown of the flaw, attackers have been spotted attempting to exploit it. CVE-2026-21589 PoC in action (Source: watchTowr) “Exploitation attempts have now started to hit our honeypot network,” threat intelligence vendor Previdian warned late Tuesday, and shared a list of attacke