Cross-Site Request Forgery (CSRF)
Best Practical Solutions RT 3.8.0 through 3.8.9 and 4.0.0rc through 4.0.0rc7, when the CustomFieldValuesSources (aka external custom field) option is enabled, allows remote authenticated users to execute arbitrary code via unspecified vectors, as demonstrated by a cross-site request forgery (CSRF) attack.
CWE-352 - Cross-Site Request Forgery (CSRF)
Cross-Site Request Forgery (CSRF) is a vulnerability that allows an attacker to make arbitrary requests in an authenticated vulnerable web application and disrupt the integrity of the victim’s session. The impact of a successful CSRF attack may range from minor to severe, depending upon the capabilities exposed by the vulnerable application and privileges of the user. An attacker may force the user to perform state-changing requests like transferring funds, changing their email address or password etc. However, if an administrative level account is affected, it may compromise the whole web application and associated sensitive data.