Medium 6.1Published Aug 17, 2026

CVE-2026-63670ApostropheCMS: Mutation-XSS / allowedTags bypass via literal `</textarea/>` solidus close

Updated under an hour ago (2026-10-19 06:30 UTC)

Does this affect you?

It affects apostrophecms apostrophe. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for apostrophecms apostrophe

Exploited in the last 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.

CVSS: 6.1 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE): CWE-79
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Aug 18, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

apostrophecms apostrophe apostrophecms:apostrophe (from the name)	before 2.17.6	CNA record

References

https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-jxwj-j7wr-gfrwx-refsource-confirm
https://github.com/apostrophecms/apostrophe/pull/5501x-refsource-misc
https://github.com/apostrophecms/apostrophe/commit/eae1fb2b72ec5d1c27d0977509c6482a0408f725x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.