Stored XSS via unencoded Page Container icon
Published Sep 14, 2026 · Updated Sep 14, 2026
Stored XSS in Page Container icons in Concrete CMS 9.0.0 through 9.5.2 allows remote authenticated users to run script in editors' sessions. The dashboard stores an icon value without checking it against known icons, and a helper concatenates that value into an img src attribute without encoding it. Delegated Page Containers access is required to plant the value, and execution occurs when another authenticated editor or administrator opens the list or editor view, enabling session-token theft and privileged dashboard actions.
Summary
What happened
Stored XSS in Page Container icons in Concrete CMS 9.0.0 through 9.5.2 allows remote authenticated users to run script in editors' sessions. The dashboard stores an icon value without checking it against known icons, and a helper concatenates that value into an img src attribute without encoding it. Delegated Page Containers access is required to plant the value, and execution occurs when another authenticated editor or administrator opens the list or editor view, enabling session-token theft and privileged dashboard actions.
The record
- CVE
- CVE-2026-81903
- Published
- Sep 14, 2026
- Updated
- Sep 14, 2026
- Vendor
- Concrete CMS
- Product
- Concrete CMS
- Classifications
- CWE-79, T1539
- Attack vector
- adjacent
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 14, 2026CVE publishedPublication date reported by the CVE source.
- Sep 14, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=9.0.0 <=9.5.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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