Stored XSS via unescaped shortcode attributes
Published Jun 2, 2026 · Updated Jun 2, 2026
Stored cross-site scripting in jhdscript ZeM STL 1.0 and earlier allows remote authenticated users to inject scripts via shortcode attributes. The [zemstl] handler directly interpolates the url, color, and bgcolor values into HTML attributes without esc_attr() or equivalent output escaping. Contributor-level access is required to save the payload, which executes in the browser of any user who opens the affected page.
Summary
What happened
Stored cross-site scripting in jhdscript ZeM STL 1.0 and earlier allows remote authenticated users to inject scripts via shortcode attributes. The [zemstl] handler directly interpolates the url, color, and bgcolor values into HTML attributes without esc_attr() or equivalent output escaping. Contributor-level access is required to save the payload, which executes in the browser of any user who opens the affected page.
The record
- CVE
- CVE-2026-4081
- Published
- Jun 2, 2026
- Updated
- Jun 2, 2026
- Vendor
- jhdscript
- Product
- ZeM STL
- Classifications
- CWE-79, T1059.007
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 2, 2026CVE publishedPublication date reported by the CVE source.
- Jun 2, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=1.0
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
- CVE-2026-4081 zem-stl-viewer proof of conceptproof of concept · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo