FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

FreeBSD -- IPv6 UDP sendto(2) bypasses jail loopback restriction

Affected packages
15.1 <= FreeBSD-kernel < 15.1_4
15.0 <= FreeBSD-kernel < 15.0_14
14.5 <= FreeBSD-kernel < 14.5_1
14.4 <= FreeBSD-kernel < 14.4_10

Details

VuXML ID 6d92b2a3-bcce-11f1-906f-bc241121aa0a
Discovery 2026-09-29
Entry 2026-09-30

Problem Description:

The IPv6 UDP send path for unconnected sockets did not apply the jail policy of rewriting a loopback destination address to the jail's primary IPv6 address.

Impact:

A process in a classic (non-VNET) jail can send UDP datagrams to services listening on the host's IPv6 loopback address, bypassing jail network isolation.

References

CVE Name CVE-2026-101303
FreeBSD Advisory SA-26:69.udp

Copyright © 2003-2005 Jacques Vidrine and contributors.
Please see the source of this document for full copyright information.