This High severity ch.qos.logback:logback-core Dependency vulnerability was introduced in versions 7.21.0, 8.9.0, 8.13.0, 8.14.0, 8.15.0, and 8.16.0 of Bitbucket Data Center and Server.

This ch.qos.logback:logback-core Dependency 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 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 7.21: Upgrade to a release greater than or equal to 7.21.19

• Bitbucket Data Center and Server 8.9: Upgrade to a release greater than or equal to 8.9.9

• Bitbucket Data Center and Server 8.13: Upgrade to a release greater than or equal to 8.13.5

• Bitbucket Data Center and Server 8.14: Upgrade to a release greater than or equal to 8.14.4

• Bitbucket Data Center 8.15: Upgrade to a release greater than or equal to 8.15.3

• Bitbucket Data Center 8.16: Upgrade to a release greater than or equal to 8.16.2

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: A serialization vulnerability in logback receiver component part of
logback version 1.4.13, 1.3.13 and 1.2.12 allows an attacker to mount a Denial-Of-Service
attack by sending poisoned data.