CVE-2026-63670: Apostrophecms Apostrophe

Medium severity, CVSS 6.1. EPSS: 0.3% chance of exploitation in the next 30 days.

ApostropheCMS is an open-source Node.js content management system. Prior to 2.17.6, sanitizeHtml() can pass disallowed executable markup through packages/sanitize-html/index.js when textarea or xmp is included in allowedTags because a literal solidus after the raw-text end-tag name is treated as text by htmlparser2 and the ontext handler emits that content without escaping, while a browser parses the following img onerror markup as active HTML. This issue is fixed in version 2.17.6.

Affected products

• Apostrophecms Apostrophe: before 2.17.6 (fixed in 2.17.6)

Published 2026-08-17. Last modified 2026-09-09.