The scan of polyfill.io on 21 Aug 2026 reached no verdict either way (score -12). Too little was captured to judge it, which is an unknown rather than a pass.

What malware is associated with polyfill.io?

1 analysed samples communicate with this URL, including Smuggling.

How was polyfill.io checked?

A static pass resolved DNS, captured TLS and headers and followed the redirect chain, and where the fast tier allows, a headless browser rendered the page and recorded every request. Egress is SSRF-locked. Signatures that matched only page text are weighted far below one that matched a served file, because a page documenting malware matches the same rules.

polyfill.io - URL scan, 21 Aug 2026

MalwareAnalyzer by Cyble scanned polyfill.io and returned a unknown verdict (score -12). The page resolved to 104.21.62.62 on Cloudflare, Inc. in US. 2 domains and 1 IP were contacted, over 1 HTTP request. 1 malware sample communicates with this URL (Smuggling). This is a point-in-time observation from 21 Aug 2026; the page may have changed since.

Scan result

Verdict: unknown (score -12) · Confidence 15%
Scanned URL: https://polyfill.io/v3/polyfill.min.js?features=fetch
Domain: polyfill.io · IP: 104.21.62.62 · AS13335 · US
Server: cloudflare
Page title: 401 Authorization Required
HTTP status: 401 · text/html
TLS issuer: C=US, O=Google Trust Services, CN=WE1 · valid to Oct 19 08: · subject CN=polyfill.io
HTTP requests captured: 1
Scan tier: fast · observed 2026-08-21 20:27:25 UTC

Malware communicating with this URL (1)

These samples were observed contacting or being served from polyfill.io. Each links to its full analysis.

Smuggling - referenced · ad13fe15582def936d8edae946492709 · first seen 2026-08-21

Antivirus & YARA (0 of 47 engines)

No engine flagged this page's content.

Why this verdict

Valid TLS, no impersonation or off-origin credential post

Detected technologies

Cloudflare
Cloudflare Insights

Contacted infrastructure

104.21.62.62 - AS13335 Cloudflare, Inc. (United States)

Observed indicators

polyfill.io
static.cloudflareinsights.com
104.21.62.62
https://polyfill.io/v3/polyfill.min.js?features=fetch
https://static.cloudflareinsights.com/beacon.min.js/v4513226cdae34746b4dedf0b4dfa099e1781791509496

Other scans of polyfill.io (5)

This host has been scanned before. Each scan is a separate observation, so a verdict here does not carry over to the others.

17 Aug 2026 - unknown · https://www.tapuionoticias.com/ckfinder/files/9118243508.pdf
17 Aug 2026 - unknown · https://www.tapuionoticias.com/ckfinder/files/9118243508.pdf
17 Aug 2026 - unknown · https://www.tapuionoticias.com/ckfinder/files/9118243508.pdf
17 Aug 2026 - unknown · https://www.tapuionoticias.com/ckfinder/files/9118243508.pdf
12 Aug 2026 - suspicious · https://wkd-uk.com/wp-content/plugins/super-forms/uploads/php/files/f707dcca5d1d90d3637b9656840dfb94

Questions about polyfill.io

Is polyfill.io safe?: The scan of polyfill.io on 21 Aug 2026 reached no verdict either way (score -12). Too little was captured to judge it, which is an unknown rather than a pass.
What malware is associated with polyfill.io?: 1 analysed samples communicate with this URL, including Smuggling.
How was polyfill.io checked?: A static pass resolved DNS, captured TLS and headers and followed the redirect chain, and where the fast tier allows, a headless browser rendered the page and recorded every request. Egress is SSRF-locked. Signatures that matched only page text are weighted far below one that matched a served file, because a page documenting malware matches the same rules.

Scanned at the fast tier - see how URL scanning works.

Scan another URL · Latest analyzed threats · All scans of polyfill.io

Scanned on MalwareAnalyzer by Cyble · Open interactive scan