CVE-2021-21307

Name: CVE-2021-21307
Creator: NVD / NIST
Published: 2021-02-11T19:15:13.313+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 89.19%

Last modified Jun 17, 2026

CVE-2021-21307 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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. EPSS estimates a 89.19% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

89.19%

99.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-862

Affected Software

Vendor	Product	Versions
Lucee	Lucee Server	>= 5.3.5.00, < 5.3.5.96
Lucee	Lucee Server	>= 5.3.6.00, < 5.3.6.68
Lucee	Lucee Server	>= 5.3.7.00, < 5.3.7.47

References

http://ciacfug.org/blog/updating-lucee-as-part-of-a-vulnerability-alert-responsePatch, Third Party Advisory
http://packetstormsecurity.com/files/163864/Lucee-Administrator-imgProcess.cfm-Arbitrary-File-Write.htmlExploit, Third Party Advisory, VDB Entry
https://dev.lucee.org/t/lucee-vulnerability-alert-november-2020/7643Vendor Advisory
https://github.com/httpvoid/writeups/blob/main/Apple-RCE.mdExploit, Third Party Advisory
https://github.com/lucee/Lucee/commit/6208ab7c44c61d26c79e0b0af10382899f57e1caPatch, Third Party Advisory
https://github.com/lucee/Lucee/security/advisories/GHSA-2xvv-723c-8p7rProduct
https://portswigger.net/daily-swig/security-researchers-earn-50k-after-exposing-critical-flaw-in-apple-travel-portalPress/Media Coverage, Third Party Advisory
http://ciacfug.org/blog/updating-lucee-as-part-of-a-vulnerability-alert-responsePatch, Third Party Advisory
http://packetstormsecurity.com/files/163864/Lucee-Administrator-imgProcess.cfm-Arbitrary-File-Write.htmlExploit, Third Party Advisory, VDB Entry
https://dev.lucee.org/t/lucee-vulnerability-alert-november-2020/7643Vendor Advisory
https://github.com/httpvoid/writeups/blob/main/Apple-RCE.mdExploit, Third Party Advisory
https://github.com/lucee/Lucee/commit/6208ab7c44c61d26c79e0b0af10382899f57e1caPatch, Third Party Advisory
https://github.com/lucee/Lucee/security/advisories/GHSA-2xvv-723c-8p7rProduct
https://portswigger.net/daily-swig/security-researchers-earn-50k-after-exposing-critical-flaw-in-apple-travel-portalPress/Media Coverage, Third Party Advisory

Timeline

Published: Feb 11, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21307?

How severe is CVE-2021-21307?

CVE-2021-21307 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 89.19% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21307?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-21307?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST