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JSONP enabled by default

Freshover 13 years ago
Mar 14, 20260 views
Confidence Score87%
87%

Problem

why the hell is JSONP enabled by default?? that's VERY unsecure if a developer doesn't know about it and leaves it open: JSONP enables cross-origin requests, meaning your server is giving your content away to any other server! this can even lead to sensitive user data disclosure to third parties when used in conjunction with XSS. please, set the default JSONP setting to disabled as soon as possible: default Express servers must NOT accept any callback parameter by default, callback parameters must be explicitly examined by the developer on a per-request basis. thank you.

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1 Fix

Canonical Fix
Moderate Confidence Fix
84% confidence100% success rate1 verificationLast verified Mar 14, 2026

Solution: JSONP enabled by default

Low Risk

sorry, I probably need to better clarify what I'm talking about. here: http://expressjs.com/api.html#app-settings I can read: "jsonp callback Enables jsonp callback support, enabled by default" which, to the best of my knowledge, is very wrong. thanks again!

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  1. 1

    sorry, I probably need to better clarify what I'm talking about.

    sorry, I probably need to better clarify what I'm talking about.

  2. 2

    here: http://expressjs.com/api.html#app-settings

    here: http://expressjs.com/api.html#app-settings

  3. 3

    I can read: "jsonp callback Enables jsonp callback support, enabled by default"

    which, to the best of my knowledge, is very wrong.

Validation

Resolved in expressjs/express GitHub issue #1304. Community reactions: 0 upvotes.

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Worked: 1
Last verified Mar 14, 2026

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Environment

Submitted by

AC

Alex Chen

2450 rep

Tags

expressnode.jsapi