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CVE-2026-23209

Vulnérabilité élevée dans Linux (Linux)

CVSS 7.8 · Élevée
EPSS 0.1%
Linux•Linux•Versions : <=6.1.*, 6.6.124, <=6.12.*, aa5fd0fb77486b8a6764ead8627baa14790e4280, 0, 6.12.70, 6.18.10, <=5.10.*, <=6.6.*, <f8db6475a83649689c087a8f52486fcc53e627e9, 6.1.163, <cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66, <986967a162142710076782d5b93daab93a892980, <4.9, <=6.18.*, <5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a, 5.10.250, <=*, 4.9, <=5.15.*, 6.19, <11ba9f0dc865136174cb98834280fb21bbc950c7, <da5c6b8ae47e414be47e5e04def15b25d5c962dc, <c43d0e787cbba569ec9d11579ed370b50fab6c9c, 5.15.200

Description

In the Linux kernel, the following vulnerability has been resolved: macvlan: fix error recovery in macvlan_common_newlink() valis provided a nice repro to crash the kernel: ip link add p1 type veth peer p2 ip link set address 00:00:00:00:00:20 dev p1 ip link set up dev p1 ip link set up dev p2 ip link add mv0 link p2 type macvlan mode source ip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20 ping -c1 -I p1 1.2.3.4 He also gave a very detailed analysis: <quote valis> The issue is triggered when a new macvlan link is created with MACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or MACVLAN_MACADDR_SET) parameter, lower device already has a macvlan port and register_netdevice() called from macvlan_common_newlink() fails (e.g. because of the invalid link name). In this case macvlan_hash_add_source is called from macvlan_change_sources() / macvlan_common_newlink(): This adds a reference to vlan to the port's vlan_source_hash using macvlan_source_entry. vlan is a pointer to the priv data of the link that is being created. When register_netdevice() fails, the error is returned from macvlan_newlink() to rtnl_newlink_create(): if (ops->newlink) err = ops->newlink(dev, &params, extack); else err = register_netdevice(dev); if (err < 0) { free_netdev(dev); goto out; } and free_netdev() is called, causing a kvfree() on the struct net_device that is still referenced in the source entry attached to the lower device's macvlan port. Now all packets sent on the macvlan port with a matching source mac address will trigger a use-after-free in macvlan_forward_source(). </quote valis> With all that, my fix is to make sure we call macvlan_flush_sources() regardless of @create value whenever "goto destroy_macvlan_port;" path is taken. Many thanks to valis for following up on this issue.

Gravité et risque d'exploitation

CVE-2026-23209 obtient un score CVSS de 7.8/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.14 %, ce qui la place devant 3.0 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, 6.6.124, <=6.12.*, aa5fd0fb77486b8a6764ead8627baa14790e4280, 0, 6.12.70, 6.18.10, <=5.10.*, <=6.6.*, <f8db6475a83649689c087a8f52486fcc53e627e9, 6.1.163, <cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66, <986967a162142710076782d5b93daab93a892980, <4.9, <=6.18.*, <5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a, 5.10.250, <=*, 4.9, <=5.15.*, 6.19, <11ba9f0dc865136174cb98834280fb21bbc950c7, <da5c6b8ae47e414be47e5e04def15b25d5c962dc, <c43d0e787cbba569ec9d11579ed370b50fab6c9c, 5.15.200) 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

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