It was found that the use of Pipeline: Classpath Step Jenkins plugin enables a bypass of the Script Security sandbox for users with SCM commit access, as well as users with e.g. Job/Configure permission in Jenkins.
Exploitability
AV:NAC:HPR:LUI:NScope
S:CImpact
C:HI:HA:H8.5/CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:HOther