What’s Vulnerable › Vulnerabilities

CVE-2021-28145

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-03-18 · updated 2026-06-17
• Weakness: CWE-79

Description

Concrete CMS (formerly concrete5) before 8.5.5 allows remote authenticated users to conduct XSS attacks via a crafted survey block. This requires at least Editor privileges.

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

• https://documentation.concrete5.org/developers/introduction/version-history/855-release-notes
• https://www.concrete5.org/developers/security
• https://documentation.concrete5.org/developers/introduction/version-history/855-release-notes
• https://www.concrete5.org/developers/security

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