CVE-2024-3179: Concrete CMS version 9 before 9.2.8 and previous versions before 8.5.16 are vulnerable to Stored XSS in the Custom Class page

Severity: medium (CVSS 4.8 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: 2024-04-03 · updated 2026-06-17
Weakness: CWE-79

Description

Concrete CMS version 9 before 9.2.8 and previous versions before 8.5.16 are vulnerable to Stored XSS in the Custom Class page editing. Prior to the fix, a rogue administrator could insert malicious code in the custom class field due to insufficient validation of administrator provided data. The Concrete CMS security team gave this vulnerability a CVSS v3.1 score of 3.1 with a vector of AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:L/A:L https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator . Thanks Alexey Solovyev for reporting.

Affected products

Concrete CMS: before 8.5.16; from 9.0.0 before 9.2.8 — fixed in 8.5.16, 9.2.8

How to fix

Upgrade to a fixed version: Concrete CMS 8.5.16, 9.2.8. Check the vendor advisory for mitigations.

References

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