This High severity DoS (Denial of Service) vulnerability was introduced in versions 10.0.0, 10.1.1, 10.2.0, and 10.3.0 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 cause a resource to be unavailable for its intended users by temporarily or indefinitely disrupting services of a host connected to a network 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 10.2.4

• Bitbucket Data Center 10.3: Upgrade to a release greater than or equal to 10.3.1

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

The National Vulnerability Database provides the following description for this vulnerability: The brace-expansion library generates arbitrary strings containing a common prefix and suffix. From 5.0.0 to before 5.0.6, the max option was being applied too late. When expanding a single large numeric range like

, the sequence generation loop generates all 10 million intermediate elements before the max limit is applied With max=10, the output is correctly limited to 10 items, but the process still allocates ~505 MB and spends ~800ms building the full intermediate array. This vulnerability is fixed in 5.0.6.