PHP Warning: Undefined array key 0 in Has_Multiple_Admins.php line 93 (multisite

Hello, and thanks again for confirming this is a plugin-side edge case.

I ran the checks you suggested and validated the result directly in our multisite environment.

Codebase checks:

I searched our codebase under wp-content (active plugins, mu-plugins, and theme functions.php files) for anything that might modify the super admin list before Site Kit reads it.

• No filters found for:
  • site_admins
  • pre_option_site_admins
  • pre_site_option_site_admins
  • site_option_site_admins
• No custom assignments to global $super_admins found outside WordPress core.
• Only read-only consumers of get_super_admins() were found (for example Wordfence, Freemius-based plugins, and Site Kit itself).

Runtime verification (WP-CLI):

get_super_admins() returned: type=array count=1 keys=[5] key0_exists=no

Raw multisite option value: site_admins = {“5″:”svenms”}

Conclusion:

This confirms the edge case:

• The array is non-empty, so !empty($super_admins) is true.
• But index 0 does not exist (sparse/non-zero-based keys).
• Therefore $super_admins[0] triggers “Undefined array key 0” on PHP 8+.

Additional check (2FA plugin):

We also reviewed the active 2FA plugin (wp-2fa). It does not reference site_admins, get_super_admins, or related site_admins filters, so it does not appear to be causing this condition.

Safer access pattern suggestion:

Option 1: $login = reset($super_admins);

Option 2: $super_admins = array_values($super_admins); $login = $super_admins[0] ?? null;

Thank you.

• This reply was modified 3 weeks ago by svenms.
• This reply was modified 3 weeks ago by svenms.
• This reply was modified 3 weeks ago by svenms.