Stored XSS via ignored HTML purification output
Published Sep 30, 2026 · Updated Sep 30, 2026
Stored cross-site scripting in baserCMS before 5.3.1 or 5.4.1 allows remote authenticated users with article-editing rights to run scripts in visitors' browsers. BcValidation::containsScript() discarded HTMLPurifier's sanitized output and judged submitted article content using error messages, letting encoded script-bearing markup pass validation and be stored. Exploitation requires article-editing permission and a visitor to view the affected content; the script runs in that visitor's browser, not on the server.
Summary
What happened
Stored cross-site scripting in baserCMS before 5.3.1 or 5.4.1 allows remote authenticated users with article-editing rights to run scripts in visitors' browsers. BcValidation::containsScript() discarded HTMLPurifier's sanitized output and judged submitted article content using error messages, letting encoded script-bearing markup pass validation and be stored. Exploitation requires article-editing permission and a visitor to view the affected content; the script runs in that visitor's browser, not on the server.
The record
- CVE
- CVE-2026-93463
- Published
- Sep 30, 2026
- Updated
- Sep 30, 2026
- Vendor
- baserCMS Users Community
- Product
- baserCMS
- Classifications
- CWE-79, T1059.007
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 30, 2026CVE publishedPublication date reported by the CVE source.
- Sep 30, 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=0 <5.3.1
- Affected versionversion=0 <5.4.1
What conditions does exploitation require?
What is affected?
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.
Activity data is delayed. The latest report is Sep 28, 2026.
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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