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Fencer Vulns
high 7.5

CVE-2026-101303 json

IPv6 UDP sendto(2) bypasses jail loopback restriction

published 2026-10-15 25 d ago modified 2026-10-20 20 d ago also EUVD-2026-101874

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

Summary

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.

Patch / fix

  • FreeBSD FreeBSD p1, p4, p10, p14

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
23 d ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

  • FreeBSD FreeBSD

Classification

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

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.