Is CheerpJ Applet Runner safe?

Low risk

CheerpJ Applet Runner exposes a proxy frame that fetches caller-supplied URLs and returns the responses.

Its CheerpJ frame is web-accessible to any site and accepts a posted message port without checking the sender's origin. After the user grants this extension access to a site's origin, a page that embeds the frame can ask it to fetch URLs from that origin and receive the response bytes and metadata through the message port.

Part of this rating comes from analysis signals we haven't published as detailed findings yet.

Leaning Technologies Ltdv2026.9Chrome Web Store
20Risk
Who publishes it

Leaning Technologies Limited - 1 other listing from the same operator, 1 of them carrying a finding

What this publisher told the store about itself, and the other listings that told it the same thing.

Publisher
Leaning Technologies Ltd
Declared legal entity
Leaning Technologies Limited
Registered address
3rd Floor, 207 Regent Street, London W1B 3HH, GB
Registered contact
Stefano De Rossi

Same operator - 1 listing

Published under a different store account, but sharing the registered address, contact or declared legal entity this one gave the store.

AI-generated. Findings may contain errors. Those marked Verified have been manually reviewed.

Publishers can request a review.

Updated 30 September 2026bbmolahhldcbngedljfadjlognfaaein