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CVE-2026-64543

Vulnérabilité élevée dans Linux (Linux)

CVSS 7.8 · Élevée
EPSS 0.1%
Linux•Linux•Versions : <=6.1.*, 7.1.5, 6.18.40, <=6.12.*, <f05b3f4c78370469286879c765f5a1dd39dbcd32, <b65289e1c3f352a9f92c6e19713ddd647e033253, 0, <=7.1.*, 5.15.216, <a0c5fdeb5fa257f8c6d469af266bc087cb5de6a2, <380413cdfd29fb9fa486c82889132b680c4983c5, <4.17, <=5.10.*, <=6.6.*, 6.12.97, 6.1.183, 4.17, <=6.18.*, 6.6.145, <ec7d54d8cc1723921d671e3272b427c96366506f, <4da2ac7749411971e1b222b992da5a172ce45f98, 25b0b9c4e835ffaa65b61c3efe2e28acf84d0259, <=*, <=5.15.*, <5e215bf1c47fdddf8203a0fe80a0ed594065f101, <1579342d71133da7f00daa02c75cebec7372097b, 5.10.265, 7.2

Description

In the Linux kernel, the following vulnerability has been resolved: tipc: fix use-after-free of the discoverer in tipc_disc_rcv() bearer_disable() frees b->disc with tipc_disc_delete()'s plain kfree(), but tipc_disc_rcv() still dereferences b->disc in RX softirq under rcu_read_lock() (tipc_udp_recv -> tipc_rcv -> tipc_disc_rcv). L2 bearers are safe thanks to the synchronize_net() in tipc_disable_l2_media(), but the UDP bearer defers that call to the cleanup_bearer() workqueue, so the discoverer is freed with no grace period: BUG: KASAN: slab-use-after-free in tipc_disc_rcv (net/tipc/discover.c:149) Read of size 8 at addr ffff88802348b728 by task poc_tipc/184 <IRQ> tipc_disc_rcv (net/tipc/discover.c:149) tipc_rcv (net/tipc/node.c:2126) tipc_udp_recv (net/tipc/udp_media.c:391) udp_rcv (net/ipv4/udp.c:2643) ip_local_deliver_finish (net/ipv4/ip_input.c:241) </IRQ> Freed by task 181: kfree (mm/slub.c:6565) bearer_disable (net/tipc/bearer.c:418) tipc_nl_bearer_disable (net/tipc/bearer.c:1001) The bearer is freed with kfree_rcu(); free the discoverer the same way. Add an rcu_head to struct tipc_discoverer and free it and its skb from an RCU callback. Because the RCU callback (tipc_disc_free_rcu) lives in module text, a call_rcu() that is still pending when the tipc module is unloaded would invoke a freed function. Add an rcu_barrier() to tipc_exit() after the bearer subsystem has been torn down, so all pending discoverer callbacks have run before the module text goes away. Reachable from an unprivileged user namespace: the TIPCv2 genl family is netnsok and its bearer commands have no GENL_ADMIN_PERM. Needs CONFIG_TIPC and CONFIG_TIPC_MEDIA_UDP.

Gravité et risque d'exploitation

CVE-2026-64543 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 0.13 %, ce qui la place devant 2.0 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, 7.1.5, 6.18.40, <=6.12.*, <f05b3f4c78370469286879c765f5a1dd39dbcd32, <b65289e1c3f352a9f92c6e19713ddd647e033253, 0, <=7.1.*, 5.15.216, <a0c5fdeb5fa257f8c6d469af266bc087cb5de6a2, <380413cdfd29fb9fa486c82889132b680c4983c5, <4.17, <=5.10.*, <=6.6.*, 6.12.97, 6.1.183, 4.17, <=6.18.*, 6.6.145, <ec7d54d8cc1723921d671e3272b427c96366506f, <4da2ac7749411971e1b222b992da5a172ce45f98, 25b0b9c4e835ffaa65b61c3efe2e28acf84d0259, <=*, <=5.15.*, <5e215bf1c47fdddf8203a0fe80a0ed594065f101, <1579342d71133da7f00daa02c75cebec7372097b, 5.10.265, 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

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