CVE-2026-63670
ApostropheCMS: Mutation-XSS / allowedTags bypass via literal `</textarea/>` solidus close
CVSS Score
6.1
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-79 |
| Vendor | apostrophecms |
| Product | apostrophe |
| Published | Aug 17, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None
Affected Versions
apostrophecms / apostrophe
< 2.17.6