CVE-2021-21307: Remote Code Exploit in Lucee Admin

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 89.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-02-11 · updated 2026-06-17
Weakness: CWE-862

Description

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: from 5.3.5.00 before 5.3.5.96; from 5.3.6.00 before 5.3.6.68; from 5.3.7.00 before 5.3.7.47 — fixed in 5.3.5.96, 5.3.6.68, 5.3.7.47

How to fix

Upgrade to a fixed version: Lucee 5.3.5.96, 5.3.6.68, 5.3.7.47. Check the vendor advisory for mitigations.

References

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