CVE-2021-21307
CriticalExploitedPublic exploitIn Lucee Admin before versions 5.3.7.47, 5.3.6.68 or 5.3.5.96 there is an unauthenticated remote code exploit.
Published Feb 11, 2021 · Updated Jul 9, 2026 · Also known as GHSA-2xvv-723c-8p7r
Key Facts
Patch immediately- CVE-2021-21307 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Lucee Server, Lucee.
- It is exploited in the wild, listed in Industry KEV feed, CIRCL KEV since Oct 14, 2023. Public exploit code is available.
- EPSS estimates a 89% probability of exploitation in the next 30 days.
- Fixed versions are available, including Lucee Server 5.3.5.96.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
89%
Higher than 99.7% of all scored CVEs
Exploited in the wild
Yes
2 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2021-21307 brief as a PDF
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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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Nov 29, 2023 | n/a | Not reported |
| CIRCL KEV | Oct 14, 2023 | n/a | Not reported |
Required action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Lucee ServerLucee | See advisory | 5.3.5.96 |
| Lucee | >= >= 5.3.5.0, < 5.3.5.96 | n/a |
Patched Releases
Lucee Server
5.3.5.96
Timeline
Publicly disclosed
Feb 11, 2021
Added to CIRCL KEV
Oct 14, 2023
Added to Industry KEV feed
Nov 29, 2023
Last updated
Jul 9, 2026
Weakness Type
- CWE-862 Missing Authorization
References
- advisoryhttps://dev.lucee.org/t/lucee-vulnerability-alert-november-2020/7643
- advisoryhttps://portswigger.net/daily-swig/security-researchers-earn-50k-after-exposing-critical-flaw-in-apple-travel-portal
- patchhttp://ciacfug.org/blog/updating-lucee-as-part-of-a-vulnerability-alert-response
- patchhttps://github.com/lucee/Lucee/commit/6208ab7c44c61d26c79e0b0af10382899f57e1ca
- exploithttp://packetstormsecurity.com/files/163864/Lucee-Administrator-imgProcess.cfm-Arbitrary-File-Write.html
FAQ
Common Questions.
Lucee Server is a dynamic, Java based (JSR-223), tag and scripting language used for rapid web application development.
Affected: Lucee Server; Lucee versions >= >= 5.3.5.0, < 5.3.5.96. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed, CIRCL KEV since Oct 14, 2023.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including Lucee Server 5.3.5.96.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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