This High severity DoS (Denial of Service) vulnerability was introduced in versions 9.4.23, 10.2.6, and 10.4.2 of Bitbucket 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 Bitbucket 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:

• Bitbucket Data Center 10.2: Upgrade to a release greater than or equal to 10.2.8
• Bitbucket Data Center 9.4: Upgrade to a release greater than or equal to 9.4.26

See the release notes (https://confluence.atlassian.com/bitbucketserver/release-notes). You can download the latest
version of Bitbucket Data Center and Server from the download center
(https://www.atlassian.com/software/bitbucket/download-archives).

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

jsoup through 1.23.2, fixed in commit 862ba2f, contains an uncontrolled resource consumption vulnerability in XmlTreeBuilder that allows remote attackers to exhaust JVM heap memory by supplying a deeply nested XML document with uniquely-namespaced elements. The builder copies the entire inherited namespace map on every start element, causing quadratic time and memory complexity, which attackers can exploit to trigger an OutOfMemoryError and terminate the application.