This High severity org.apache.avro:avro Dependency vulnerability was introduced in versions 6.5 of Confluence Data Center and Server.

This org.apache.avro:avro Dependency vulnerability, with a CVSS Score of 7.3 and a CVSS Vector of CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L allows an unauthenticated attacker to expose assets in your environment susceptible to exploitation which has low impact to confidentiality, low impact to integrity, low impact to availability, and requires no user interaction.

Atlassian recommends that Confluence 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:

• Confluence Data Center and Server 7.19: Upgrade to a release greater than or equal to 7.19.30

• Confluence Data Center and Server 8.5: Upgrade to a release greater than or equal to 8.5.18

• Confluence Data Center and Server 9.1: Upgrade to a release greater than or equal to 9.1.1

See the release notes (https://confluence.atlassian.com/doc/confluence-release-notes-327.html). You can download the latest version of Confluence Data Center and Server from the download center (https://www.atlassian.com/software/confluence/download-archives).

The National Vulnerability Database provides the following description for this vulnerability: Schema parsing in the Java SDK of Apache Avro 1.11.3 and previous versions allows bad actors to execute arbitrary code.
Users are recommended to upgrade to version 1.11.4  or 1.12.0, which fix this issue.