Request Smuggling org.apache.tomcat.embed:tomcat-embed-core Dependency in Bitbucket Data Center and Server

This High severity org.apache.tomcat.embed:tomcat-embed-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 org.apache.tomcat.embed:tomcat-embed-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:H/A:N allows an unauthenticated attacker to expose assets in your environment susceptible to exploitation which has no impact to confidentiality, high impact to integrity, no 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 7.21.21

• 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: Improper Input Validation vulnerability in Apache Tomcat.Tomcat from 11.0.0-M1 through 11.0.0-M10, from 10.1.0-M1 through 10.1.15, from 9.0.0-M1 through 9.0.82 and from 8.5.0 through 8.5.95 did not correctly parse HTTP trailer headers. A trailer header that exceeded the header size limit could cause Tomcat to treat a single request as multiple requests leading to the possibility of request smuggling when behind a reverse proxy.

Users are recommended to upgrade to version 11.0.0-M11 onwards, 10.1.16 onwards, 9.0.83 onwards or 8.5.96 onwards, which fix the issue.