CVE-2021-21307: Lucee Server

Critical severity, CVSS 9.8. EPSS: 89.2% chance of exploitation in the next 30 days.

Lucee Server is a dynamic, Java based (JSR-223), tag and scripting language used for rapid web application development. In Lucee Admin before versions 5.3.7.47, 5.3.6.68 or 5.3.5.96 there is an unauthenticated remote code exploit. This is fixed in versions 5.3.7.47, 5.3.6.68 or 5.3.5.96. As a workaround, one can block access to the Lucee Administrator.

Affected products

• Lucee Lucee Server: from 5.3.5.00, before 5.3.5.96 (fixed in 5.3.5.96); from 5.3.6.00, before 5.3.6.68 (fixed in 5.3.6.68); from 5.3.7.00, before 5.3.7.47 (fixed in 5.3.7.47)

Published 2021-02-11. Last modified 2026-06-17.