Vulnerability · Published Oct 15, 2026 · Assigned by freebsd

CVE-2026-101303IPv6 UDP sendto(2) bypasses jail loopback restriction

High 7.5

In plain English

A high-severity security flaw in FreeBSD from FreeBSD. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 11% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.2%top 88.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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. 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.

Affected products (as reported)

Vendor	Product	Versions
FreeBSD	FreeBSD	15.1-RELEASE – before p415.0-RELEASE – before p1414.5-RELEASE – before p114.4-RELEASE – before p10

Weakness: CWE-941 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

References

https://security.freebsd.org/advisories/FreeBSD-SA-26:69.udp.asc vendor-advisory