untrusted comment: verify with openbsd-69-base.pub RWQQsAemppS46K6kKuKCGjTpuS0kB439FHmBaszzP4exoLEiBJ9acGMVDfNxDXd353DAveNi/ta4uW/W/6UyQQzaemDgtMcfbg0= OpenBSD 6.9 errata 022, November 26, 2021: An unprivileged user could crash the kernel by using UNIX-domain sockets in multiple threads. Apply by doing: signify -Vep /etc/signify/openbsd-69-base.pub -x 022_unpcon.patch.sig \ -m - | (cd /usr/src && patch -p0) And then rebuild and install a new kernel: KK=`sysctl -n kern.osversion | cut -d# -f1` cd /usr/src/sys/arch/`machine`/compile/$KK make obj make config make make install Index: sys/kern/uipc_usrreq.c =================================================================== RCS file: /cvs/src/sys/kern/uipc_usrreq.c,v diff -u -p -r1.144.2.1 uipc_usrreq.c --- sys/kern/uipc_usrreq.c 30 Oct 2021 18:11:28 -0000 1.144.2.1 +++ sys/kern/uipc_usrreq.c 17 Nov 2021 21:35:00 -0000 @@ -640,6 +640,13 @@ unlock: solock(so); unp->unp_flags &= ~UNP_CONNECTING; + /* + * The peer socket could be closed by concurrent thread + * when `so' and `vp' are unlocked. + */ + if (error == 0 && unp->unp_conn == NULL) + error = ECONNREFUSED; + return (error); }