CVE-2021-3111

Severity: medium (CVSS 4.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 3.0% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-01-08 · updated 2026-06-17
Weakness: CWE-79

Description

The Express Entries Dashboard in Concrete5 8.5.4 allows stored XSS via the name field of a new data object at an index.php/dashboard/express/entries/view/ URI.

Affected products

Concrete CMS: before 8.5.5 — fixed in 8.5.5

How to fix

Upgrade to a fixed version: Concrete CMS 8.5.5. Check the vendor advisory for mitigations.

References

http://packetstormsecurity.com/files/161600/Concrete5-8.5.4-Cross-Site-Scripting.html
http://packetstormsecurity.com/files/161997/Concrete5-8.5.4-Cross-Site-Scripting.html
https://documentation.concrete5.org/developers/introduction/version-history
https://documentation.concrete5.org/developers/introduction/version-history/855-release-notes
https://github.com/Quadron-Research-Lab/CVE/blob/main/CVE-2021-3111.pdf
http://packetstormsecurity.com/files/161600/Concrete5-8.5.4-Cross-Site-Scripting.html
http://packetstormsecurity.com/files/161997/Concrete5-8.5.4-Cross-Site-Scripting.html
https://documentation.concrete5.org/developers/introduction/version-history
https://documentation.concrete5.org/developers/introduction/version-history/855-release-notes
https://github.com/Quadron-Research-Lab/CVE/blob/main/CVE-2021-3111.pdf

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