This High severity RCE (Remote Code Execution) vulnerability was introduced in version 10.3.0 of Bitbucket Data Center.

This (Remote Code Execution) vulnerability, with a CVSS Score of 7.1 and a CVSS Vector of CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H allows an unauthenticated attacker to expose assets in your environment susceptible to exploitation which has high impact to confidentiality, high impact to integrity, high impact to availability, and requires user interaction.

Atlassian recommends that Bitbucket 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:

• Bitbucket Data Center and Server 10.3: Upgrade to a release greater than or equal to 10.3.2

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:

The package grunt before 1.3.0 are vulnerable to Arbitrary Code Execution due to the default usage of the function
load() instead of its secure replacement safeLoad() of the package js-yaml inside grunt.file.readYAML.