CVE-2026-68116

Description

In the Linux kernel, the following vulnerability has been resolved: vxlan: mdb: Fix source list corruption on a failed replace When replacing the source list of an MDB remote entry, all existing sources are first marked for deletion and vxlan_mdb_remote_srcs_add() is then called to add the new source list. Sources present in the new list have their deletion mark cleared, and any sources left marked afterwards are removed. If vxlan_mdb_remote_srcs_add() fails partway through, its error path deletes all entries on the remote's source list. That rollback is only correct for its other caller, vxlan_mdb_remote_add(), where the remote was just allocated and the list contains solely entries added during the call. On the replace path the list also holds pre-existing sources, so a failed replace tears them down together with their (S, G) forwarding entries instead of leaving the entry unchanged. This is reachable from an existing (*, G) remote. An EXCLUDE filter that loses sources starts forwarding traffic that should be blocked, while an INCLUDE filter that loses sources drops traffic that should be forwarded. Mark entries created during the current pass with a new VXLAN_SGRP_F_NEW flag. On failure, delete only those entries and clear the deletion mark on the pre-existing ones, so a failed replace leaves the source list untouched. Retain the flag until the whole operation succeeds and then clear it. Also stop vxlan_mdb_remote_src_add() from deleting a pre-existing entry it only looked up when adding that entry's forwarding entry fails.

Gravité et risque d'exploitation

CVE-2026-68116 obtient un score CVSS de 7.9/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.12 %, ce qui la place devant 1.8 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions a3a48de5eade770e911d35291217bdd69ce04ef1, <=6.12.*, 6.12.101, 0, <79370b573e92e8f190eb5f9a511fa5398340d8b2, <=7.1.*, <2c54dff57606590fa4abec46bab6bea3133f1539, 6.4, <dcd9b465965422b9654f6026e8a2fa8984f74c3c, <=6.6.*, <5bc8fc1d2ff802eec839e03adef5df597421898d, 6.18.42, <6.4, 7.1.6, <=6.18.*, <54a3c27b357dfb34f327f89bfadeb998bef8051e, <=*, 6.6.148, 7.2) 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/5bc8fc1d2ff802eec839e03adef5df597421898d
• https://git.kernel.org/stable/c/2c54dff57606590fa4abec46bab6bea3133f1539
• https://git.kernel.org/stable/c/79370b573e92e8f190eb5f9a511fa5398340d8b2
• https://git.kernel.org/stable/c/54a3c27b357dfb34f327f89bfadeb998bef8051e
• https://git.kernel.org/stable/c/dcd9b465965422b9654f6026e8a2fa8984f74c3c