Stored XSS in EspoCRM before 5.6.4 allows remote attackers to execute malicious JavaScript and inject arbitrary source code into the target pages

Stored XSS in EspoCRM before 5.6.4 allows remote attackers to execute malicious JavaScript and inject arbitrary source code into the target pages. The attack begins by storing a new stream message containing an XSS payload. The stored payload can then be triggered by clicking a malicious link on the Notifications page.