Unexplained "Blocked a frame with origin" messages in console log

Question

When I view the console on many websites, including Stack Overflow, I get (often several instances of) the following error:

Error in event handler for (unknown): Blocked a frame with origin "<URL>"
from accessing a cross-origin frame. 

It would seem reasonable to expect that perhaps a few websites I use have misconfigured CORS policies but quite suddenly it appears in my log for many sites that I use where it never did before.

I'm running the latest stable Chrome (34.0.1847.131) as of today, and I have tried closing out and rebooting to no avail.

Answer 1

The problem is likely not with the websites but with a chrome extension you have installed. The stacktrace you see below that error should give you a clue which one it is.

chrome-extension://somelongextensionidhere/somejavascript.js

View your chrome extensions under settings and check "developer mode" box at the top to view the extension IDs. The problem should go away once you disable the offending extension.

Answer 2

Just wanted to add that in my instance this was being caused by the LastPass extension.

Thread available here: https://forums.lastpass.com/viewtopic.php?f=12&t=133245