FreeBSD Network Alert: Malicious IPv6 Packets Can Trigger Remote Code Execution via resolvconf (CVE-2025-14558)

A high-severity vulnerability has been disclosed in the FreeBSD networking stack, allowing attackers to achieve remote code execution by sending a malicious IPv6 router advertisement. Tracked as CVE-2025-14558, the flaw stems from a lack of input sanitisation in how rtsol and rtsold handle IPv6 SLAAC data and pass it unmodified to resolvconf. The advisory explains that resolvconf(8) does not validate its input, so shell commands disguised as a domain name can be executed on the victim’s system.

An attacker on the same network can craft packets containing such commands, with execution occurring with system privileges when processed by the vulnerable components, though router advertisements are not routable beyond the local network. According to FreeBSD-SA-25:12.rtsold[.]asc, vulnerable systems are those running rtsol(8) or rtsold(8) and the issue is local to the same network segment.

Administrators are urged to upgrade to a supported FreeBSD release dated after the correction and apply the official patch, followed by a rebuild using buildworld and installworld.