Atlassian Crowd and Crowd Data Center had the pdkinstall development plugin incorrectly enabled in release builds. Attackers who can send unauthenticated or authenticated requests to a Crowd or Crowd Data Center instance can exploit this vulnerability to install arbitrary plugins, which permits remote code execution on systems running a vulnerable version of Crowd or Crowd Data Center. All versions of Crowd from version 2.1.0 before 3.0.5 (the fixed version for 3.0.x), from version 3.1.0 before 3.1.6 (the fixed version for 3.1.x), from version 3.2.0 before 3.2.8 (the fixed version for 3.2.x), from version 3.3.0 before 3.3.5 (the fixed version for 3.3.x), and from version 3.4.0 before 3.4.4 (the fixed version for 3.4.x) are affected by this vulnerability.

This High severity RCE (Remote Code Execution) vulnerability was introduced in version 3.4.6 of Crowd Data Center and Server. This RCE (Remote Code Execution) vulnerability, with a CVSS Score of 8.0, 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 Crowd 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: Crowd Data Center and Server 3.4: Upgrade to a release greater than or equal to 5.1.6 Crowd Data Center and Server 5.2: Upgrade to a release greater than or equal to 5.2.1 See the release notes ([https://confluence.atlassian.com/crowd/crowd-release-notes-199094.html]). You can download the latest version of Crowd Data Center and Server from the download center ([https://www.atlassian.com/software/crowd/download-archive]). This vulnerability was discovered by m1sn0w and reported via our Bug Bounty program

The OpenID client application in Atlassian Crowd before version 3.6.2, and from version 3.7.0 before 3.7.1 allows remote attackers to perform a Denial of Service attack via an XML Entity Expansion vulnerability.