Vulnerability · Published Jun 12, 2026 · Assigned by GitHub_M
CVE-2026-53608@apostrophecms/seo Vulnerable to Stored XSS via Unsanitized Google Analytics / GTM ID Injected into Script Tag
High 8.7
In plain English
A high-severity cross-site scripting in @apostrophecms/seo from apostrophecms. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
ApostropheCMS is an open-source Node.js content management system. Versions up to and including 1.4.2 of the `@apostrophecms/seo` package injects the Google Analytics Tracking ID (`seoGoogleTrackingId`) and Google Tag Manager ID (`seoGoogleTagManager`) directly into `<script>` tag bodies using JavaScript template literals without any sanitization or validation. Any user with editor-level access (the default role for content managers) can set these fields to a malicious value, resulting in stored XSS that executes on every page for every visitor of the site. As of time of publication, no known patched versions are available.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @apostrophecms/seo | 1.5.0 | GHSA-wf43-fpp3-cf65 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| apostrophecms | @apostrophecms/seo | <= 1.4.2 |
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N