This High severity RCE (Remote Code Execution) vulnerability was introduced in version 5.2 of Confluence Data Center and Server. This RCE (Remote Code Execution) vulnerability, with a CVSS Score of 7.2, allows an authenticated attacker to execute arbitrary code which has high impact to confidentiality, high impact to integrity, high impact to availability, and requires no user interaction.  Atlassian recommends that Confluence Data Center and Server customers upgrade to latest version. If you are unable to do so, upgrade your instance to one of the specified supported fixed versions. See the release notes https://confluence.atlassian.com/doc/confluence-release-notes-327.html You can download the latest version of Confluence Data Center and Server from the download center https://www.atlassian.com/software/confluence/download-archives. This vulnerability was found internally.

A template injection vulnerability on older versions of Confluence Data Center and Server allows an unauthenticated attacker to achieve RCE on an affected instance. Customers using an affected version must take immediate action. Most recent supported versions of Confluence Data Center and Server are not affected by this vulnerability as it was ultimately mitigated during regular version updates. However, Atlassian recommends that customers take care to install the latest version to protect their instances from non-critical vulnerabilities outlined in Atlassian’s January Security Bulletin.

This Template Injection vulnerability allows an authenticated attacker, including one with anonymous access, to inject unsafe user input into a Confluence page. Using this approach, an attacker is able to achieve Remote Code Execution (RCE) on an affected instance. Publicly accessible Confluence Data Center and Server versions as listed below are at risk and require immediate attention. See the advisory for additional details Atlassian Cloud sites are not affected by this vulnerability. If your Confluence site is accessed via an atlassian.net domain, it is hosted by Atlassian and is not vulnerable to this issue.