for 5.7 refer to http://www.openbsd.org/errata57.html for what has been patched
If compiling it yourself is not an option, then refer to snksnk's comment and use https://stable.mtier.org
I've tried this in the past but some ports (typically big ones like web browsers) will run out of some resource or other during the build.
Also it seems that if you build from ports all the dependencies are built from ports too, even if they're already installed as packages? It ends up taking hours in some cases.
If library bumps happened, the packages might take a while to catch up, though.
What I do is I build a release with patches I'm interested in (my own or other people's). After upgrading my machines to that release I try `pkg_add -u`. If that complains about libraries, I just wait a day or two for a new set of packages to come out and try again. Sometimes I cheat and compile the missing library in a slightly backdated src checkout, or fetch it from a system that happens to have a copy of the right .so file.
If all that is too complicated, or if you want -stable instead of -current, try mtier.