Is ZeM STL safe to use?

Laskyr does not give safety verdicts. ZeM STL is closed on wordpress.org. Closed on 2026-05-27 (reason given: Security Issue). Closed plugins get no updates through WordPress, so new security holes will not be fixed for you. Keep ZeM STL on the latest version and remove it if you do not use it.

Which versions of ZeM STL are vulnerable?

Known issues on record (newest first): Stored cross-site scripting (XSS) (1.0 and older). The full list with sources is on this page.

What should I do if my ZeM STL is out of date?

Take a backup, then update it from Dashboard > Updates (or run wp plugin update zem-stl-viewer). If you cannot update right away, deactivate it until you can. If you think the site was already attacked, run a free scan at https://laskyr.com/scan.

Plugins · zem-stl-viewer · data as of 2026-11-04

Is ZeM STL safe? Known vulnerabilities and latest version

Status: Closed 2026-05-27
Known issues on record: 1
Unpatched in latest: 0

What to do

Replace it. A closed plugin gets no updates through WordPress, so any hole found from now on stays open.
Deactivate and delete it once you have a replacement (Plugins → Deactivate → Delete). Deleting removes its files; deactivating alone leaves them on the server.
If you ran a vulnerable version and something looks off (spam pages, strange admins, redirects), run the free scan, or have us clean it: Emergency Cleanup, $499.

With WP-CLI, once you have a replacement: wp plugin deactivate zem-stl-viewer && wp plugin delete zem-stl-viewer

Check your version

Known vulnerabilities

1 on record, newest first. “Affected” is the version range the source gives; “fixed in” is the version the source names, or (marked *) the first wordpress.org release after the last affected version. 1 record(s) do not state which versions are affected.

medium 6.4 CVE-2026-4081 · published 2026-06-02

Stored cross-site scripting (XSS) in ZeM STL (1.0 and older)

Affected: 1.0 and older
Fixed in: unknown
Access needed (per CVSS): Needs a low-level account (e.g. subscriber)
Range from: CVE record (the advisory publisher) · score by Wordfence

Details from the advisory

The ZeM STL plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the [zemstl] shortcode in all versions up to and including 1.0. This is due to insufficient input sanitization and output escaping on user-supplied shortcode attributes, specifically the 'url', 'color', and 'bgcolor' parameters. These attribute values are directly interpolated into HTML attribute context without being passed through esc_attr() or any other escaping function. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

NVD CVE-2026-4081 Wordfence advisory Plugin source

Recent activity

2026-05-27 — closed on wordpress.org (Security Issue).
2026-06-02 — Stored cross-site scripting (XSS) disclosed (CVE-2026-4081), fix version not stated.

Free. We check the CVE feeds every day and email you only when a new issue for ZeM STL (zem-stl-viewer) is published or a fix ships. Unsubscribe in one click.

Browse vulnerabilities

Types found in this plugin: Cross-site scripting (XSS) (1)

Where this data comes from

Version, last update, installs, closure: wordpress.org/plugins/zem-stl-viewer (Plugins API), fetched 2026-11-04.
Vulnerabilities: NIST National Vulnerability Database (NVD), checked 2026-11-04. This product uses data from the NVD API but is not endorsed or certified by the NVD.
Each record links to its CVE page and to the original advisory (Wordfence, Patchstack or WPScan) where there is one. We only list a CVE here when its references or its advisory name this exact plugin, so a few real issues may be missing; none should be about a different plugin. Spot an error? Email Daniel.

Badge for your site or docs (states facts with a date, not a verdict):

<a href="https://laskyr.com/plugins/zem-stl-viewer"><img src="https://laskyr.com/plugins/zem-stl-viewer/badge.svg" alt="ZeM STL vulnerability status"></a>

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