URL: <https://savannah.gnu.org/bugs/?68722>
Summary: macOS 27 + Bash 5.3.20(1) = ifconfig prints redacted
MAC addresses 02:00:00:00:00:00
Group: The GNU Bourne-Again SHell
Submitter: luckman212
Submitted: Mon 28 Sep 2026 07:24:53 PM UTC
Category: None
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: None
Status: None
Privacy: Public
Assigned to: None
Open/Closed: Open
Discussion Lock: Unlocked
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Follow-up Comments:
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Date: Mon 28 Sep 2026 07:24:53 PM UTC By: Luke Hamburg <luckman212>
I don't know if this is really a Bash bug or not (struggling to see how it
even could be, but…)
Since "upgrading" to macOS 27 (and now 27.0.1) the /sbin/ifconfig utility is
not outputting hardware MAC addresses - instead printing only what seems to be
a redacted value of 02:00:00:00:00:00
The builtin bash 3.2.57(1) does not suffer this oddity, nor does the builtin
/bin/zsh.
I reproduced this on 3 separate systems before reporting it here. If you feel
this is just an Apple issue somehow, I will close this and file a Feedback to
the giant /dev/null black hole void that is Apple Support. If any other debug
outputs or tests are needed, happy to provide them.
As you can see in the examples below, the Bash 5 binary results in a redacted
MAC, while the /bin/bash and /bin/zsh invocations show the real one.
mini4% /opt/homebrew/bin/bash --noprofile --norc -c '/sbin/ifconfig en0 | grep
ether'
ether 02:00:00:00:00:00
mini4% /bin/bash --noprofile --norc -c '/sbin/ifconfig en0 | grep ether'
ether d0:11:e5:1a:27:7a
mini4% /bin/zsh --no-rcs -c '/sbin/ifconfig en0 | grep ether'
ether d0:11:e5:1a:27:7a
mini4% /bin/bash --version
GNU bash, version 3.2.57(1)-release (arm64-apple-darwin26)
Copyright (C) 2007 Free Software Foundation, Inc.
mini4% /opt/homebrew/bin/bash --version
GNU bash, version 5.3.20(1)-release (aarch64-apple-darwin27.0.0)
Copyright (C) 2025 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
mini4% sw_vers
ProductName: macOS
ProductVersion: 27.0.1
BuildVersion: 26A434
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