# Why does Firefox 17.0.1 user agent string not contain the correct version number? [closed]

Background: I know the practice of user agent sniffing isn't approved, but I encountered a bug in Firefox 17.0 that enabled HTML and Javascript source code editing in the WYSIWYG editor FCKEditor which is bundled into Coldfusion 10 and prior versions regardless if that editor is officially supported or not. I'm trying to prevent version 17.0 from being able to expose this vulnerability, but UA sniffing in this case has proven to be not useable as it falsely returns the incorrect browser version for 17.0.1 users.

Question: Why is the user agent in Firefox 17.0.1 actually listed as 17.0 in the user agent string?

Details: My Firefox 17.0.1 user agent shows as: Mozilla/5.0 (Windows NT 6.0; WOW64; rv:17.0) Gecko/20100101 Firefox/17.0

I expected the user agent to look like this without question: Mozilla/5.0 (Windows NT 6.0; WOW64; rv:17.0) Gecko/20100101 Firefox/17.0.1

I suspect this is the source of the behavior, but I'm not sure: https://bugzilla.mozilla.org/show_bug.cgi?id=792054

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## closed as off topic by Al E., Alex, Eight Days of Malaise, ChrisF♦Dec 12 '12 at 9:19

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For future reference, web browser feature/settings questions are best asked at Super User. –  Al E. Dec 14 '12 at 14:36
Right, I sometimes suffer from GCE regarding exactly where a question belongs. Quite honestly, it would be helpful if StackExchange could provide a question migration means as corrective action rather than down-voting alone. –  Sn3akyP3t3 Dec 14 '12 at 15:35

According to the Firefox release notes, there were some troubles with user-agent containing Firefox/17.0.1, so they changed user-agent string back to 17.0.