CVE-2026-3884 Cross-site scripting in spin.js
An attacker can execute arbitrary JavaScript in the user's browser via prototype pollution in the spin.js library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-3884?
CVE-2026-3884 is a medium-severity cross-site scripting vulnerability in spin.js, published on 11 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Versions of the package spin.js before 3.0.0 are vulnerable to Cross-site Scripting (XSS) via the spin() function that allows a creation of more than 1 alert for each 'target' element. An attacker would need to set an arbitrary key-value pair on Object.prototype through a crafted URL achieving a prototype pollution first, before being able to execute arbitrary JavaScript in the context of the user's browser.
Weakness: CWE-79
Which versions are affected by CVE-2026-3884?
It affects 1 product.
Products include Spin.js Spin.js.
How do I fix CVE-2026-3884?
No fix has been published for CVE-2026-3884 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-3884 being exploited?
There is no known exploitation of CVE-2026-3884 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-3884, GHSA-h99f-r56h-cmrp, UBUNTU-CVE-2026-3884.