As of now we doubt that the proposed patch helps and we even fear that it could make things worst. Thus, as long as there is we have no description of an attack we won't do anything about it.

... https://lists.gnupg.org/pipermail/gcrypt-devel/2019-July/004760.html

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Folks, I was just wondering if I could get an update on where we are with this bug. It seems we aren't sure if it's a real issue or not. What's the latest thought?

Werner, I interpreted jwilik's patch as admission of a problem from upstream, and reported it as such to CVE. I felt that since this does not effect the main platforms (ARM and x86_64) it would not be a big deal. If I interpreted wrong, I am sorry.

I assigned the CVE, but yes it needs more facts.

Andreas, I wonder on which grounds you assigned a CVE for this claimed side-channel attack. The mentioned paper is about an old RSA side-channel and not on AES. I would like to see more facts than the reference to a guy who knows PPC pretty well.

This bug has been assigned CVE-2019-12904. http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-12904