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commit 09e1b0e3f6facc1af2dbcfef204f0aaa8718772b
Author: Florian Weimer <fweimer>
Date:   Mon May 20 21:54:57 2019 +0200

    libio: Remove codecvt vtable [BZ #24588]
    
    The codecvt vtable is not a real vtable because it also contains the
    conversion state data.  Furthermore, wide stream support was added to
    GCC 3.0, after a C++ ABI bump, so there is no compatibility
    requirement with libstdc++.
    
    This change removes several unmangled function pointers which could
    be used with a corrupted FILE object to redirect execution.  (libio
    vtable verification did not cover the codecvt vtable.)
    
    Reviewed-by: Yann Droneaud <ydroneaud>
    Reviewed-by: Adhemerval Zanella <adhemerval.zanella>

Please backport patch to Fedora (if required):
Fedora 31
Fedora 30
Fedora 29

The removal of the unmangled function pointers is something that users aren't going to notice, but we want to clean this up to stay in sync with this code upstream because we may want other changes in this same code. Therefore we aren't going to document this.

Glibc testsuite runs with no regression

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2020:1828