IPv6 UDP sendto(2) bypasses jail loopback restriction

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-101303
StatePUBLISHED
Assignerfreebsd
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-15 07:17:57 UTC
Updated2026-10-20 00:17:27 UTC
DescriptionThe 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS: 0.003630000 probability, percentile 0.287000000 (date 2026-10-20)

Problem Types: CWE-941 | CWE-941 CWE-941: Incorrectly Specified Destination in a Communication Channel

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Freebsd Freebsd 14.4 - All All
Operating System Freebsd Freebsd 14.4 p1 All All
Operating System Freebsd Freebsd 14.4 p2 All All
Operating System Freebsd Freebsd 14.4 p3 All All
Operating System Freebsd Freebsd 14.4 p4 All All
Operating System Freebsd Freebsd 14.4 p5 All All
Operating System Freebsd Freebsd 14.4 p6 All All
Operating System Freebsd Freebsd 14.4 p7 All All
Operating System Freebsd Freebsd 14.4 p8 All All
Operating System Freebsd Freebsd 14.4 p9 All All
Operating System Freebsd Freebsd 14.5 - All All
Operating System Freebsd Freebsd 15.0 - All All
Operating System Freebsd Freebsd 15.0 p1 All All
Operating System Freebsd Freebsd 15.0 p10 All All
Operating System Freebsd Freebsd 15.0 p11 All All
Operating System Freebsd Freebsd 15.0 p12 All All
Operating System Freebsd Freebsd 15.0 p13 All All
Operating System Freebsd Freebsd 15.0 p2 All All
Operating System Freebsd Freebsd 15.0 p3 All All
Operating System Freebsd Freebsd 15.0 p4 All All
Operating System Freebsd Freebsd 15.0 p5 All All
Operating System Freebsd Freebsd 15.0 p6 All All
Operating System Freebsd Freebsd 15.0 p7 All All
Operating System Freebsd Freebsd 15.0 p8 All All
Operating System Freebsd Freebsd 15.0 p9 All All
Operating System Freebsd Freebsd 15.1 - All All
Operating System Freebsd Freebsd 15.1 p1 All All
Operating System Freebsd Freebsd 15.1 p2 All All
Operating System Freebsd Freebsd 15.1 p3 All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA FreeBSD FreeBSD affected 15.1-RELEASE p4 release Not specified
CNA FreeBSD FreeBSD affected 15.0-RELEASE p14 release Not specified
CNA FreeBSD FreeBSD affected 14.5-RELEASE p1 release Not specified
CNA FreeBSD FreeBSD affected 14.4-RELEASE p10 release Not specified

References

ReferenceSourceLinkTags
security.freebsd.org/advisories/FreeBSD-SA-26:69.udp.asc [email protected] security.freebsd.org Patch, Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Yuxiang Yang, Yizhou Zhao, Ao Wang, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM-5.1 from Z.ai (en)

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