What’s Vulnerable › Vulnerabilities

CVE-2023-28820

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-04-28 · updated 2026-06-17
• Weakness: CWE-79

Description

Concrete CMS (previously concrete5) before 9.1 is vulnerable to stored XSS in RSS Displayer via the href attribute because the link element input was not sanitized.

Affected products

• Concrete CMS: before 9.1.0 — fixed in 9.1.0

How to fix

Upgrade to a fixed version: Concrete CMS 9.1.0. Check the vendor advisory for mitigations.

References

• https://github.com/concretecms/concretecms/releases
• https://www.concretecms.org/about/project-news/security/concrete-cms-security-advisory-2023-04-20
• https://github.com/concretecms/concretecms/releases
• https://www.concretecms.org/about/project-news/security/concrete-cms-security-advisory-2023-04-20

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