CVE-2026-89565

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

Gravité et risque d'exploitation

CVE-2026-89565 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.17 %, ce qui la place devant 6.3 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <=6.1.*, <=6.12.*, <1909df2d066424767429e13053eb9701263430ef, <6d8c5b266d0035a061573843a7243be068eb6118, 0, <fd01f1a3ed4a189a784654f7c69eb565872f2e12, 7.2.4, cfc7381b3002756b1dcada32979e942aa3126e31, 6.1.188, <=6.6.*, 6.6.157, <31e4be21dacee49395013caae28576484a049a4f, <4.9, <=6.18.*, <=7.2.*, <=*, 4.9, <6776efe4a52f289a3fc18f8adf19b035a7d8e1bb, <c4dc23de4cc75e4e304170b31bb8aeeacd5cb990, 6.18.50, 6.12.109, 7.3) est présent sur votre parc.
• Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
• À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
• Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

• https://git.kernel.org/stable/c/1909df2d066424767429e13053eb9701263430ef
• https://git.kernel.org/stable/c/c4dc23de4cc75e4e304170b31bb8aeeacd5cb990
• https://git.kernel.org/stable/c/6d8c5b266d0035a061573843a7243be068eb6118
• https://git.kernel.org/stable/c/31e4be21dacee49395013caae28576484a049a4f
• https://git.kernel.org/stable/c/fd01f1a3ed4a189a784654f7c69eb565872f2e12
• https://git.kernel.org/stable/c/6776efe4a52f289a3fc18f8adf19b035a7d8e1bb