CVE-2026-101303 IPv6 UDP sendto(2) bypasses jail loopback restriction
Attackers in a FreeBSD jail can bypass network isolation to reach host IPv6 loopback services via UDP.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-101303?
CVE-2026-101303 is a high-severity vulnerability in Freebsd Freebsd, published on 15 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-941
Which versions are affected by CVE-2026-101303?
It affects 1 product.
Products include Freebsd Freebsd.
How do I fix CVE-2026-101303?
No fix has been published for CVE-2026-101303 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-101303 being exploited?
There is no known exploitation of CVE-2026-101303 in the wild and no public exploit code.