PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-53608 apostrophecms CVE debrief

ApostropheCMS is an open-source Node.js content management system. Versions up to and including 1.4.2 of the `@apostrophecms/seo` package inject unsanitized user input into `<script>` tag bodies using JavaScript template literals. This allows any user with editor-level access to inject malicious JavaScript, resulting in stored XSS that executes on every page for every visitor. The vulnerability has a CVSS score of 8.7 and is classified as HIGH severity.

Vendor
apostrophecms
Product
@apostrophecms/seo
CVSS
HIGH 8.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-12
Original CVE updated
2026-06-15
Advisory published
2026-06-12
Advisory updated
2026-06-15

Who should care

Users of ApostropheCMS with the `@apostrophecms/seo` package installed, particularly those with editor-level access.

Technical summary

The `@apostrophecms/seo` package directly injects user-controlled input (`seoGoogleTrackingId` and `seoGoogleTagManager`) into `<script>` tags without sanitization or validation. This allows for stored XSS attacks, which can be exploited by users with editor-level access.

Defensive priority

HIGH

Recommended defensive actions

  • Upgrade to a patched version of the `@apostrophecms/seo` package (if available).
  • Restrict editor-level access to trusted users.
  • Monitor for suspicious activity on the site.

Evidence notes

The vulnerability is confirmed by the CVE record and the NVD detail page. A security advisory is available on the ApostropheCMS GitHub page [ref-4].

Sources and references

Verified primary and authoritative sources

  • CVE-2026-53608 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-53608

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-53608 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-53608

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.