CVE Catalog

CVE-2026-98306

Low risk· EPSS 8%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.18%

8th percentile - higher than 8% of all known CVEs

Summary

In the Linux kernel seg6, decap_and_validate() did not set the IPSKB_L3SLAVE flag in IPCB for IPv4 during IPIP decapsulation, although it did so for IPv6. As a result, SRv6 packets decapsulated on a VRF-enslaved interface did not reach local sockets as expected. The fix sets IPSKB_L3SLAVE for IPv4.

Risk Assessment

Incorrect packet handling in VRF environments can lead to routing errors, traffic leaking outside the VRF, or network security issues. It affects SRv6 configurations with VRF.

Recommendation

Update the Linux kernel to a patched version. Until then, verify VRF and SRv6 configuration for unexpected packet routing.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

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 limited to the default VRF. Set IPSKB_L3SLAVE for IPv4 in decap_and_validate(), which already does the same for IPv6. The socket lookup then matches the decapsulated packet like any other packet received on that enslaved interface. Such a packet matches an unbound UDP or TCP socket only when udp_l3mdev_accept or tcp_l3mdev_accept is set.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS