CVE-2024-8660: Stored XSS in the "Top Navigator Bar" block

Severity: medium (CVSS 4.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-09-17 · updated 2026-06-17
Weakness: CWE-79

Description

Concrete CMS versions 9.0.0 through 9.3.3 are affected by a stored XSS vulnerability in the "Top Navigator Bar" block. Since the "Top Navigator Bar" output was not sufficiently sanitized, a rogue administrator could add a malicious payload that could be executed when targeted users visited the home page.The Concrete CMS Security Team gave this vulnerability a CVSS v4 score of 4.6 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N . This does not affect versions below 9.0.0 since they do not have the Top Navigator Bar Block. Thanks, Chu Quoc Khanh for reporting.

Affected products

Concrete CMS: from 9.0.0 before 9.3.4 — fixed in 9.3.4

How to fix

Upgrade to a fixed version: Concrete CMS 9.3.4. Check the vendor advisory for mitigations.

References

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