medium6.1
CVE-2026-63670
ApostropheCMS: Mutation-XSS / allowedTags bypass via literal `</textarea/>` solidus close
Impact
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 packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | sanitize-html | <= 2.17.5 | 2.17.6 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-jxwj-j7wr-gfrw
- https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-jxwj-j7wr-gfrw
- https://nvd.nist.gov/vuln/detail/CVE-2026-63670
- https://github.com/apostrophecms/apostrophe/pull/5501
- https://github.com/apostrophecms/apostrophe/commit/eae1fb2b72ec5d1c27d0977509c6482a0408f725