CVE-2026-89565

/// Technical description

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

ipip: fix skb leak in collect_md mode when metadata_dst allocation fails

In collect_md mode ipip_tunnel_rcv() returns 0 without freeing the skb

when ip_tun_rx_dst() fails to allocate the metadata_dst. ipip_rcv() and

mplsip_rcv() are registered as xfrm_tunnel handlers, so tunnel4_rcv()

and tunnelmpls4_rcv() read the zero return as "the packet has been

consumed" and do not free it either. The skb is leaked.

The other tunnel drivers all dispose of the packet at this point:

ip6_tunnel.c jumps to its drop label, ip_gre.c and ip6_gre.c return

PACKET_REJECT, which makes gre_rcv() free the skb. Only ipip returns 0.

Jump to the existing drop label instead. It frees the skb and still

returns 0, so the packet keeps being reported as consumed, which is what

we want here: the outer header has already been pulled, and neither the

remaining handlers nor an ICMP unreachable have any use for it.

Triggering this needs an ipip or mp

/// 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