Errata patches for kernel fork process group have been released for
OpenBSD 7.7 and 7.8.

Binary updates for the amd64, arm64 and i386 platform are available
via the syspatch utility.  Source code patches can be found on the
respective errata page:

  https://www.openbsd.org/errata77.html
  https://www.openbsd.org/errata78.html