CVE-2026-84371
ApostropheCMS is an open-source Node.js content management system, and sanitize-html provides a simple HTML sanitizer with a clear API. From version 1.9.0 until version 2.17.7, packages/sanitize-html/index.js validates an animation value attribute as one flat URL and does not recognize that attributeName selecting href or xlink:href gives the sibling values, from, to, or by attribute SVG SMIL URL semantics. In configurations that allow the animate, animateColor, animateMotion, animateTransform, or set elements, a values list can begin with a safe fragment and contain a later executable destination that survives allowedSchemesAppliedToAttributes checking. When the sanitized SVG is rendered, the browser can copy that later destination into the live link, and a victim who activates the link can execute script in the application's origin. This issue is fixed in version 2.17.7.
What this means for your business
- An attacker can use it remotely, over a network, with an ordinary user login, but only after tricking someone into an action such as opening a file or a link.
- FIRST's prediction model gives it a 0.2% chance of attack attempts being seen in the next 30 days, ranking above 8% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
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Scoring
- CVSS
- 5.4 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N- Weakness
- CWE-79
- Assigned by
- security-advisories@github.com
Dates
- Published
- 2026-09-01
- Last modified
- 2026-09-09
- Sources
- NVD
References
- https://github.com/apostrophecms/apostrophe/blob/main/packages/sanitize-html/CHANGELOG.md
- https://github.com/apostrophecms/apostrophe/commit/1135516a1a4a8f9638641c460488a43d8af20081
- https://github.com/apostrophecms/apostrophe/commit/38ff1106c8176b16c2da9872acd9b449adcbb949
- https://github.com/apostrophecms/apostrophe/pull/5552
- https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-g8qq-57p8-ggw5