Quick answers
- Is CVE-2026-101303 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-101303 being exploited in the wild.
- How severe is CVE-2026-101303?
- High severity, with a CVSS score of 7.5, published 15 October 2026.
- Which products and versions are affected?
- Freebsd 15.0, 15.1, 14.4, 14.5 and earlier supported versions.
- Is there a fix for CVE-2026-101303?
- Yes: fixed in FreeBSD 15.1-RELEASE-p4, 15.0-RELEASE-p14, 14.5-RELEASE-p1, 14.4-RELEASE-p10. Until then: No workaround is available. Systems using only VNET jails, or classic jails without an IPv6 address, are not affected. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-101303 attacked?
- It is attacked over the network, in an operating system.
- Am I affected by CVE-2026-101303?
- Check whether you run Freebsd at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: FreeBSD 15.1-RELEASE-p4, 15.0-RELEASE-p14, 14.5-RELEASE-p1, 14.4-RELEASE-p10
No workaround is available. Systems using only VNET jails, or classic jails without an IPv6 address, are not affected.
Technical details
The IPv6 UDP send path for unconnected sockets fails to apply the jail policy that rewrites loopback destination addresses to the jail's primary IPv6 address. A jailed process can exploit this to send UDP datagrams directly to IPv6 loopback services, bypassing network isolation that exists for IPv4 and connected IPv6 sockets. The vulnerability affects classic (non-VNET) jails with IPv6 addressing on all supported FreeBSD versions.
Affected products
- FreeBSD FreeBSD 15.0, 15.1, 14.4, 14.5 and earlier supported versions
Timeline
- 2026-09-29: disclosed: FreeBSD security advisory published
- 2026-09-28: patched: Fix committed to stable/15