CVE-2026-63670 PUBLISHED

ApostropheCMS: Mutation-XSS / allowedTags bypass via literal `</textarea/>` solidus close

Assigner: GitHub_M
Reserved: 17.07.2026 Published: 17.08.2026 Updated: 17.08.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS Score: 6.1

Product Status

Vendor apostrophecms
Product apostrophe
Versions
  • Version < 2.17.6 is affected

References

Problem Types

  • CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE