CVE Catalog

CVE-2026-89565

Low risk· EPSS 6%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.17%

6th percentile - higher than 6% of all known CVEs

Summary

In the Linux kernel, in collect_md mode ipip_tunnel_rcv() returns 0 without freeing the skb when ip_tun_rx_dst() fails to allocate the metadata_dst. Since ipip_rcv() and mplsip_rcv() are registered as xfrm_tunnel handlers, tunnel4_rcv() and tunnelmpls4_rcv() read the zero return as 'packet consumed' and do not free it either, leaking the skb.

Risk Assessment

The skb leak on atomic allocation failure can lead to kernel memory exhaustion and system crash with ipip or mplsip tunnels in collect_md mode.

Recommendation

Update the Linux kernel to a version where ipip_tunnel_rcv() jumps to the drop label that frees the skb on this path.

Related vulnerabilities

Original NVD description (English source)

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 mplsip tunnel in collect_md mode and an atomic allocation failure, which is why it has gone unnoticed.

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