Cut in sidewall if tyre - is it still OK?

[EK993]

No idea how this happened - maybe pothole damage looking at the accompanying graze on the alloy?? I now have a cut in the sidewall of the tyre on our RRS - it doesn't look too deep. Is the tyre still OK or is it dangerous?

[EK993]

I trimmed the rubber off and it really isn't deep at all.