Without both issue is clarified the board will keep all other matters before it pending.

As the sentence is a type 1 conditional sentence, use of ‘Unless’ which means ‘Except on the condition that’ instead of ‘Without’ will be more appropriate.
Second, as ‘both’ suggests ‘two’, the noun that is followed by it must be in plural form.
The correct formation will be – “Unless both issues are clarified, the board will keep all other matters before it pending.