The Customer Context Filter in Atlassian Jira Service Desk Server and Jira Service Desk Data Center before 3.9.17, from 3.10.0 before 3.16.10, from 4.0.0 before 4.2.6, from 4.3.0 before 4.3.5, from 4.4.0 before 4.4.3, and from 4.5.0 before 4.5.1 allows remote attackers with portal access to view arbitrary issues in Jira Service Desk projects via authorization bypass. Note that when the 'Anyone can email the service desk or raise a request in the portal' setting is enabled, an attacker can grant themselves portal access, allowing them to exploit the vulnerability.