CVE-2026-101303 PUBLISHED

IPv6 UDP sendto(2) bypasses jail loopback restriction

Assigner: freebsd
Reserved: 28.09.2026 Published: 15.10.2026 Updated: 15.10.2026

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.

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.

Product Status

Vendor FreeBSD
Product FreeBSD
Versions Default: unknown
  • affected from 15.1-RELEASE to p4 (excl.)
  • affected from 15.0-RELEASE to p14 (excl.)
  • affected from 14.5-RELEASE to p1 (excl.)
  • affected from 14.4-RELEASE to p10 (excl.)

Credits

  • Yuxiang Yang, Yizhou Zhao, Ao Wang, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM-5.1 from Z.ai finder

References

Problem Types

  • CWE-941: Incorrectly Specified Destination in a Communication Channel CWE