CVE-2021-39114: 
Confluence Server vulnerability analysis and mitigation

Atlassian Confluence Server and Data Center were affected by a security vulnerability (CVE-2021-39114) that allowed users with valid accounts to execute arbitrary Java code or run system commands through OGNL payload injection. The vulnerability affected multiple versions: those before 6.13.23, versions 6.14.0 to 7.4.11, versions 7.5.0 to 7.11.6, and versions 7.12.0 to 7.12.5. The issue was discovered and reported in August 2021 (Atlassian Jira).

The vulnerability involves Object-Graph Navigation Language (OGNL) injection, allowing authenticated users to execute arbitrary Java code or system commands on affected Confluence Data Center instances. The vulnerability received a CVSS severity score of 8.8, categorizing it as High severity (Atlassian Jira).

When exploited, this vulnerability enables authenticated users to execute arbitrary Java code and system commands on the affected Confluence Server or Data Center instance, potentially leading to complete system compromise (CVE Mitre).

Atlassian released fixed versions to address this vulnerability: 6.13.23, 7.4.11, 7.11.6, 7.12.5, and 7.13.0. Users of affected versions should upgrade to the appropriate fixed version based on their current installation (Atlassian Jira).