This High severity PrivEsc (Privilege Escalation) vulnerability was introduced in versions:

9.12.0, 10.3.0, 10.4.0, and 10.5.0 of Jira Core Data Center and Server

5.12.0, 10.3.0, 10.4.0, and 10.5.0 of Jira Service Management Data Center and Server

This PrivEsc (Privilege Escalation) vulnerability, with a CVSS Score of 7.2, allows an attacker to perform actions as a higher-privileged user. 

Atlassian recommends that Jira Core Data Center and Server and Jira Service Management 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:

Jira Core Data Center and Server 9.12: Upgrade to a release greater than or equal to 9.12.20

Jira Service Management Data Center and Server 5.12: Upgrade to a release greater than or equal to 5.12.20

Jira Core Data Center 10.3: Upgrade to a release greater than or equal to 10.3.5

Jira Service Management Data Center 10.3: Upgrade to a release greater than or equal to 10.3.5

Jira Core Data Center 10.4: Upgrade to a release greater than or equal to 10.6.0

Jira Service Management Data Center 10.4: Upgrade to a release greater than or equal to 10.6.0

Jira Core Data Center 10.5: Upgrade to a release greater than or equal to 10.5.1

Jira Service Management Data Center 10.5: Upgrade to a release greater than or equal to 10.5.1

See the release notes. You can download the latest version of Jira Core Data Center and Jira Service Management Data Center from the download center. 

This vulnerability was reported via our Atlassian (Internal) program.

AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

https://confluence.atlassian.com/pages/viewpage.action?pageId=1561365992

https://jira.atlassian.com/browse/JRASERVER-78766

https://jira.atlassian.com/browse/JSDSERVER-16206