FreeBSD-SA-25:12.rtsold.asc clarification needed

mike tancsa <[email protected]> Mon, 22 Dec 2025 15:17:49 -0500
Newsgroups gmane.os.freebsd.security.general
Message-ID <[email protected]>
Just trying to better understand this issue as it says no work around is 
available yet if ipv6 is disabled, this seems like a work around ?

No workaround is available.  Users not using IPv6, and IPv6 users that do not
configure the system to accept router advertisement messages, are not affected.
A network interface listed by ifconfig(8) accepts router advertisement messages
if the string "ACCEPT_RTADV" is present in the nd6 option list.


The issue seems to be in userland with the patch being
--- usr.sbin/rtsold/rtsol.c.orig
+++ usr.sbin/rtsold/rtsol.c

And more specifically, to be vulnerable, does rtsold need to be actually running ? Or does the program get called by the kernel somehow. ie. I need
rtsold_enable="YES" in /etc/rc.conf
and seeing
ACCEPT_RTADV
in ifconfig is not actually sufficient to be vulnerable to this ?

Is patching the userland daemon enough ? It seems to be

"Restart the applicable daemons, or reboot the system."


     ---Mike