Emerging Threat: (CVE-2026-21580) Confluence Privilege Escalation via Unauthenticated Stored XSS
CVE-2026-21580 is a stored cross-site scripting vulnerability in Atlassian Confluence Data Center and Server, which the vendor advisory groups together with a privilege escalation component and a security misconfiguration weakness. An attacker persists crafted HTML or JavaScript on a vulnerable instance, and that payload executes later in the browser of whichever user views the affected content. The vulnerability carries a CVSS 4.0 base score of 8.6.