Summary
The issue being described below affects google translate and is not
exactly an open redirect. However the results can be the same under
certain conditions.
The following issue can be used as an open redirect when:

    Potential victim must not block javascripts from being executed in
his/her browser.
    Potential victim’s browser must not warn him/her about redirections.
    Potential victim’s browser must allow breaking out of iframes.

E.x visit the following link with firefox:
http://translate.google.com/translate?u=http://www.solvix.gr/accomplished.html

Details
When you want to translate a webpage you can visit
http://translate.google.com/translate?u=yoursite where “yoursite” is the
webpage you want to translate. Of course you can add and other
parameters like “sl=” and ”tl=” if you want to specify the source
language and the language you want your site to be translated to. But
lets keep it simple.
If you try to create a redirect, the redirection will happen inside
google’s frame. For example the following url:
http://translate.google.com/translate?u=http://www.solvix.gr/notaccomplished.html
notaccomplished.html has the following code:

<script type=”text/javascript”>
{
window.location.assign(“http://www.solvix.gr/notaccomplished2.html”)
}
</script>

will redirect you from http://www.solvix.gr/notaccomplished.html to
http://www.solvix.gr/notaccomplished2.html
But you are still inside google’s frame.
But what will happen if you just try to get yourself out of google’s frame?
Hmmm then you just get yourself out of google’s frame. That simple.
Check the following url:
http://translate.google.com/translate?u=http://www.solvix.gr/accomplished.html
You will be redirected in my new blog, without any warning.
accomplished.html has the following code
<script language=’Javascript’>

if (top.location!= self.location) {
top.location = self.location.href
}

</script>

<script>
{
window.location.assign(“http://www.solvix.gr”)
}
</script>

Conclusion
This issue is caused because google translate allows the execution of
javascript from the remote site. However, this is not an XSS. Javascript
is not executed on google’s domain.
Some browsers do not allow you to break the iframe (at least not with my
code above) while others warn you about the redirection. However some of
the most common browsers like firefox and Internet Explorer 8 will be
affected.

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Tested and working on:

Firefox 24.0

Firefox 23.0.1

I.E 8.0.6001

Opera 12.16 (Opera warns about the redirection but you can still escape
from the frames. Check the following url:

http://translate.google.com/translate?u=http://www.solvix.gr/or8.html )

Not working:

Konqueror Version 4.10.5 Using KDE Development Platform 4.10.5
(https://bugs.kde.org/show_bug.cgi?id=57038)

I.E 10

Google Chrome 30.0.1599.69 m

Google Chrome Version 31.0.1650.12 beta (browser warns about the
redirection)

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