Patches to vulnerabilities and critical issues are usually being applied into minor releases.
They’ve ported it to multiple releases starting from 5.3.1
That’s probably why you see it on your side.
Here’s the exact path in 5.3 branch: 983bc55f66844626fe47e137e8057123d90d133a
I don’t see this patch on the 5.2 though. It should still work on 5.2 and lower