CORS Unblock

Name: CORS Unblock
Rating: 3.8387 (31 reviews)
Author: Balvin

No more CORS error by appending 'Access-Control-Allow-Origin: *' header to local and remote web requests when enabled

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CORS Unblock is a powerful Chrome extension designed to eliminate Cross-Origin Resource Sharing (CORS) errors by appending custom Access-Control-Allow-Origin and related headers to all browser requests. Users can easily toggle the extension on or off from the toolbar and customize allowed HTTP methods such as GET, PUT, POST, DELETE, and more through the context menu.

It supports a wide range of HTTP methods including WEBDAV-specific ones and provides configurable options to respect existing server headers or overwrite them. This extension is ideal for developers and testers working with cross-origin APIs or web services who need seamless control over CORS policies without server-side changes. Comprehensive documentation and bug reporting are available on its GitHub repository.

Add-on Developer Tools Programming Productivity Web3

By:

Balvin

Daily users:

7,008 -39

Rating:

3.84

(31)

Version:

0.3.8 Last updated: 2024-02-11

Version code:

5690645

Creation date:

2019-01-22

Risk:

Permissions:

storage
<all_urls>
webRequest
webRequestBlocking
declarativeNetRequest
contextMenus

Size:

206.35KB

URLs:

Website

Full description:

Source:

Firefox Browser Add-ons

Updated:

a day ago

Ranking

# 943 ▲ 5

Other rankings

#96 in Web Development ▲ 1

#203 in Privacy & Security

#10 in unblock keyword 67

#27 in block ads keyword 95 ▲ 1

#36 in mock keyword 18

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Other platforms

CORS Unblock (v0.5.2)

100,000 4.10

(175)

CORS Unblock (v0.5.2)

69,496 4.30

(12)

User reviews

Users appreciate that the CORS Unblock add-on helps bypass CORS restrictions easily, especially useful for frontend developers and includes useful features like header modification. However, many report it does not work reliably on recent Firefox versions and causes issues such as playback failures on YouTube. There is also a consistent request for a whitelist option to avoid unintended interference with certain sites.

Pros

Effectively bypasses CORS issues for testing purposes.
Allows modification of "Access-Control-Expose-Headers", which is helpful.
Simple to enable or disable with a click on the icon.
Works well for frontend developers needing quick CORS unblocking.

Cons

Does not work consistently, with several users reporting it fails or is broken as of recent Firefox versions and dates (e.g., September 2023).
Lacks a whitelist option to restrict domains, causing problems on some sites when enabled.
Causes playback issues on some websites like YouTube when active.

Recent reviews

by 远离*****, 2025-03-24

Un desastre...no funciona...como si no existiera..

by ma*****, 2025-02-16

by 退出*****, 2025-02-10

View all user reviews ›

Extension safety

Risk impact

Risk impact measures the level of extra permissions an extension has access to. A low risk impact extension cannot do much harms, whereas a high risk impact extension can do a lot of damage like stealing your password, bypassing your security settings, and accessing your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.

CORS Unblock requires a few sensitive permissions. Exercise caution before installing.

Risk impact analysis details

Critical Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
High ****** *** ********* ** ******* *** ******* ******* ** ****** *** *** ******** ******

Risk likelihood

Risk likelihood measures the probability that a Firefox add-on may turn malicious. This is determined by the publisher and the Firefox add-on reputation on Firefox Browser Add-ons, the amount of time the Firefox add-on has been around, and other signals about the Firefox add-on. Our algorithms are not perfect, and are subject to change as we discover new ways to detect malicious extensions. We recommend that you always exercise caution when installing a Firefox add-on.

CORS Unblock has earned a fairly good reputation and likely can be trusted.

Risk likelihood analysis details

High This extension has low user count. Unpopular extensions may not be stable or safe.
Low **** ********* *** ******* **** **** * ****** **** ***** ******** *** **** ****** ** ** ****** *** *****
Low **** ********* *** ***** **** **** * ****** **** ***** ********** *** **** ****** ** ** ****** *** *****
Good **** ********* *** **** **** *******

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