XSS in Spin.js
CVE-2026-3884
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.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (16.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 17th percentile — 16.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Spin.js
- Spin.js — versions 0
Weakness classification (CWE)
References
- security.snyk.io/vuln/SNYK-JS-SPINJS-15445079 (Third Party Advisory)
- gist.github.com/ericcornelissen/1a73e28fa50c3009b0eb51ad2fc19f25 (Broken Link)
Frequently asked questions
- What is CVE-2026-3884?
- CVE-2026-3884 is a medium-severity vulnerability in Spin.js, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-03-11.
- How severe is CVE-2026-3884?
- Medium severity. CVSS v3 base score is 6.1 out of 10.