XSS in Apostrophecms @Apostrophecms/seo
CVE-2026-53608
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.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.002 (11.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.7 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N.
Affected products
- Apostrophecms @Apostrophecms/seo — versions <= 1.4.2
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
Frequently asked questions
- What is CVE-2026-53608?
- CVE-2026-53608 is a high-severity vulnerability in Apostrophecms @Apostrophecms/seo, classified under Cross-site Scripting. CVSS score: 8.7/10. Published 2026-06-12.
- How severe is CVE-2026-53608?
- High severity. CVSS v3 base score is 8.7 out of 10.