This indicates an attack attempt to exploit a Directory Traversal vulnerability in Atlassian Confluence.
The vulnerability is due to insufficient sanitizing of user supplied inputs in the application. Successful attacks may allow a remote attackers to use a specially crafted request with directory-traversal sequences to retrieve sensitive information and remote code execution.
Atlassian Confluence Server before version 6.6.12
Atlassian Confluence Server from version 6.7.0 before 6.12.3
Atlassian Confluence Server from version 6.13.0 before 6.13.3
Atlassian Confluence Server from version 6.14.0 before 6.14.2
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems.
Apply patch if available from the vendor's website.