CVE-2026-98306

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

seg6: set IPSKB_L3SLAVE from IP6SKB_L3SLAVE on IPIP decapsulation

When an SRv6 packet arrives on an interface enslaved to a VRF,

vrf_ip6_rcv() sets IP6SKB_L3SLAVE in IP6CB, but decap_and_validate()

has never set IPSKB_L3SLAVE in IPCB. The bit stayed clear in the

common case, and with CONFIG_IPV6_MIP6 the leftover frag_max_size of

a reassembled outer packet could even set it, with no VRF involved.

Commit 44930446dde4 ("ipv6: seg6: clear IPv4 control block on IPIP

decapsulation") then made the unreliable bit reliably clear.

The effect of the missing flag is visible with End.DX4 when a

delivery to a local address of the node reaches the socket lookup.

For example, a UDP socket bound to the enslaved ingress interface

does not receive any of the decapsulated packets, while an unbound

socket outside the VRF does.

This contradicts Documentation/networking/vrf.rst: by default the

scope of an unbound UDP or TCP socket is lim

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References