However, sometime between 1.2.1.2 (exclusive) and 1.2.3 (inclusive), a regression occurred in zlib, and this bug was reintroduced.
So, I strongly suspect the regression was squashed (again) in version 1.2.4.
Given the massive dependencies on zlib, I'd be very hesitant to drop 1.2.5 as an update on F12/F13 (to say nothing of RHEL, where updating to 1.2.5 is -DNO_CHANCE). But if it is possible to fix the regression against 1.2.3 (which is what F12, F13, RHEL5, and RHEL6 all run), we should do so.
This is the *exact* same patch that the zlib developers used to fix the bug originally.
So I think the only real question at this point is: was this regression intentional (e.g., because it was later discovered that the patch caused problems), or unintentional?
I've read through the zlib Changelog from version 1.2.1.2 through 1.2.3, but I can't see any indication why the fix was removed.
This was never fixed for F13. And since F14 and later do not suffer from this bug, there's no reason to keep this bug open. Closing as WONTFIX.