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CVE-2026-72323

Vulnérabilité critique dans Linux (Linux)

CVSS 9.8 · Critique
EPSS 0.7%
Linux•Linux•Versions : <40a1e998cb266ed4cb529a0bb4fee2b0ba732702, <=6.1.*, 7.1.5, 6.18.40, <=6.12.*, <8d4394ffa40508e0de72f464af351f6ca6a6cdc3, 2.6.12, <7b19c0f81ed1fdaec6bc522569be367199a9edf3, 5.10.269, 0, <=7.1.*, <2.6.12, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, <=5.10.*, <=6.6.*, 6.12.97, <165258303357e54b75fc19b341ae2a2b7c9e3910, <75e984fe0cb9e7fbde0c8ee838c61ce8573d3ea3, <d107b4c4f8274763b7ea5ab05d45cef78e4b81ba, <=6.18.*, 6.6.145, 5.15.220, <7265c747eec415ca3109a6a14a419f7ae433b780, <=*, <=5.15.*, 7.2, 6.1.187, <74b301f7f197517016befb5f5dfab01f7bc64be5

Description

In the Linux kernel, the following vulnerability has been resolved: ipv4: igmp: Fix potential UAF in igmp_gq_start_timer() A race condition exists between device teardown (inetdev_destroy) and incoming IGMP query processing (igmp_rcv), leading to a Use-After-Free in the IGMP timer callback. During device destruction, inetdev_destroy() drops the primary reference to in_device, which can drop its refcount to 0. The actual freeing of in_device memory is deferred via RCU (using call_rcu()). Concurrently, igmp_rcv() runs under RCU read lock and obtains the in_device pointer. Because the memory is RCU-protected, CPU-0 can safely dereference in_device even if its refcount has hit 0. However, if CPU-0 calls igmp_gq_start_timer() and re-arms the timer, it attempts to acquire a reference using in_dev_hold(). This increments the refcount from 0 to 1, triggering a "refcount_t: addition on 0" warning. Since the in_device memory is still scheduled to be freed after the RCU grace period (as the free callback does not check the refcount again), the device is freed while the timer is still armed. When the timer expires, it accesses the freed memory, causing a kernel panic. Fix this by using refcount_inc_not_zero() (via a new helper in_dev_hold_safe()) to prevent acquiring a reference if the device is already being destroyed. If the refcount is 0, we do not arm the timer. A similar issue in IPv6 MLD is fixed in a subsequent patch.

Gravité et risque d'exploitation

CVE-2026-72323 obtient un score CVSS de 9.8/10, soit une gravité critique. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.72 %, ce qui la place devant 52.8 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <40a1e998cb266ed4cb529a0bb4fee2b0ba732702, <=6.1.*, 7.1.5, 6.18.40, <=6.12.*, <8d4394ffa40508e0de72f464af351f6ca6a6cdc3, 2.6.12, <7b19c0f81ed1fdaec6bc522569be367199a9edf3, 5.10.269, 0, <=7.1.*, <2.6.12, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, <=5.10.*, <=6.6.*, 6.12.97, <165258303357e54b75fc19b341ae2a2b7c9e3910, <75e984fe0cb9e7fbde0c8ee838c61ce8573d3ea3, <d107b4c4f8274763b7ea5ab05d45cef78e4b81ba, <=6.18.*, 6.6.145, 5.15.220, <7265c747eec415ca3109a6a14a419f7ae433b780, <=*, <=5.15.*, 7.2, 6.1.187, <74b301f7f197517016befb5f5dfab01f7bc64be5) 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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