CVE-2024-40910
Vulnérabilité élevée dans Linux (Linux)
Description
In the Linux kernel, the following vulnerability has been resolved: ax25: Fix refcount imbalance on inbound connections When releasing a socket in ax25_release(), we call netdev_put() to decrease the refcount on the associated ax.25 device. However, the execution path for accepting an incoming connection never calls netdev_hold(). This imbalance leads to refcount errors, and ultimately to kernel crashes. A typical call trace for the above situation will start with one of the following errors: refcount_t: decrement hit 0; leaking memory. refcount_t: underflow; use-after-free. And will then have a trace like: Call Trace: <TASK> ? show_regs+0x64/0x70 ? __warn+0x83/0x120 ? refcount_warn_saturate+0xb2/0x100 ? report_bug+0x158/0x190 ? prb_read_valid+0x20/0x30 ? handle_bug+0x3e/0x70 ? exc_invalid_op+0x1c/0x70 ? asm_exc_invalid_op+0x1f/0x30 ? refcount_warn_saturate+0xb2/0x100 ? refcount_warn_saturate+0xb2/0x100 ax25_release+0x2ad/0x360 __sock_release+0x35/0xa0 sock_close+0x19/0x20 [...] On reboot (or any attempt to remove the interface), the kernel gets stuck in an infinite loop: unregister_netdevice: waiting for ax0 to become free. Usage count = 0 This patch corrects these issues by ensuring that we call netdev_hold() and ax25_dev_hold() for new connections in ax25_accept(). This makes the logic leading to ax25_accept() match the logic for ax25_bind(): in both cases we increment the refcount, which is ultimately decremented in ax25_release().
Gravité et risque d'exploitation
CVE-2024-40910 obtient un score CVSS de 8.8/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.45 %, ce qui la place devant 37.4 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions 9e1e088a57c23251f1cfe9601bbd90ade2ea73b9, 5.10.112, <5.11, <=6.1.*, 9fd75b66b8f68498454d685dc4ba13192ae069b0, 5.18, 6.10, c44a453ffe16eb08acdc6129ac4fa0192dbc0456, 6.1.95, 0, 6.9.6, <5.18, <4.20, 5.15.35, 6.6.35, <=6.6.*, b20a5ab0f5fb175750c6bafd4cf12daccf00c738, <=6.9.*, <f4df9d6c8d4e4c818252b0419c2165d66eabd4eb, 452ae92b99062d2f6a34324eaf705a3b7eac9f8b, <3c34fb0bd4a4237592c5ecb5b2e2531900c55774, 4.14.277, 4.19.240, <5.5, <5.16, 5.4.190, <52100fd74ad07b53a4666feafff1cd11436362d3, 534156dd4ed768e30a43de0036f45dca7c54818f, 5.17.2, de55a1338e6a48ff1e41ea8db1432496fbe2a62b, <=*, <4.15, <a723a6c8d4831cc8e2c7b0c9f3f0c010d4671964) 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.