This High severity DoS (Denial of Service) vulnerability was introduced in version 7.2.0 of Crowd Data Center.

This DoS (Denial of Service) vulnerability, with a CVSS Score of 7.5 and a CVSS Vector of CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H allows an unauthenticated attacker to expose assets in your environment susceptible to exploitation, which has no impact to confidentiality, no impact to integrity, high impact to availability, and requires no user interaction.

Atlassian recommends that Crowd Data Center 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 7.2: Upgrade to a release greater than or equal to 7.2.4

See the release notes (https://confluence.atlassian.com/crowd/crowd-release-notes-199094.html). You can download the
latest version of Crowd Data Center from the download center
(https://www.atlassian.com/software/crowd/download-archive).

The National Vulnerability Database provides the following description for this vulnerability:

Allocation of resources without limits or throttling vulnerability in Apache Struts. When no fixed locale is configured, the locale used for localized-text lookups is taken from the incoming request, allowing an unauthenticated remote client to cause the framework's internal localized-text caches to grow without bound and exhaust the Java heap, denying service to other users. Applications that configure a fixed locale are not affected.

This issue affects Apache Struts: from 2.0.0 through 2.3.37, from 2.5.0 through 2.5.33, from 6.0.0 through 6.10.0, from 7.0.0 through 7.2.1.

Users are recommended to upgrade to version 6.11.0 or 7.3.0, which fixes the issue.