I would stay away from it because you have no idea of what the paint is and if it has adhered good to the cinder block.
What I would do if I were in your shoes based on the amount of information I have is apply CBU or cement backer board like Durock so that you apply a non combustible material over the cinder and secure with phillips head tapcons or you can go with the hex head tapcons however they may not countersink themselves well enough and you would then have to plan on placing grout lines where the tapcon heads are, maybe.
Then if you apply the CBU you will also have a nice fresh face to attach to. Just one thought and I believe you will receive more ideas.
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