CVE-2026-63670CWE-79cross-site-scripting

CVE-2026-63670

Medium · published August 18, 2026

CVSS v3.1
6.1
EPSS
0%
Percentile
24.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.1 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00327 · 24.6th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-08-18T00:16Z
References (4)
https://github.com/apostrophecms/apostrophe/commit/eae1fb2b72ec5d1c27d0977509c6482a0408f725 · [email protected]https://github.com/apostrophecms/apostrophe/pull/5501 · [email protected]https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-jxwj-j7wr-gfrw · [email protected]https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-jxwj-j7wr-gfrw · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 17 AUG 19:49Z
    ApostropheCMS: Mutation-XSS / allowedTags bypass via literal `</textarea/>` solidus close
    cvelistv5