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CVE-2026-46123

Vulnérabilité élevée dans Linux (Linux)

CVSS 7.7 · Élevée
EPSS 0.1%
Linux•Linux•Versions : <=6.1.*, 7.0.7, <=7.0.*, <=6.12.*, <e6b4296f170d949ebba937cf6a3f247ec9550d2c, 0, 6.0.8, <4236e55b2d9d1ffd3b4bdf8ebbb86e5a0a526b4a, 9b67438e315b925a699f0178f4a48baf3d2d6ef4, 6.12.88, <b40cdd1b1370d76e9e760af4490cb4a351cceead, 5.15.209, <=6.6.*, 6.1.175, <21bd244b6de5d2fe1063c23acc93fbdd2b20d112, <6c1730099a6fc18b183bd6c1adad3b54adcaeda9, cf2719a21fdb9d4c8e9c834d279163609bef575d, 7.1, <=6.18.*, <fd91fa2678ab603dfb285416c1cf3843d7be1e41, 5.15.78, 6.1, <ed41c81d30b211a671667259c3b5feeba0e062d5, <=*, <5.15.209, <=5.15.*, 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be, 6.6.140, 6.18.30, <6.1

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: virtio_bt: clamp rx length before skb_put virtbt_rx_work() calls skb_put(skb, len) where len comes directly from virtqueue_get_buf() with no validation against the buffer we posted to the device. The RX skb is allocated in virtbt_add_inbuf() and exposed to virtio as exactly 1000 bytes via sg_init_one(). Checking len against skb_tailroom(skb) is not sufficient because alloc_skb() can leave more tailroom than the 1000 bytes actually handed to the device. A malicious or buggy backend can therefore report used.len between 1001 and skb_tailroom(skb), causing skb_put() to include uninitialized kernel heap bytes that were never written by the device. The same path also accepts len == 0, in which case skb_put(skb, 0) leaves the skb empty but virtbt_rx_handle() still reads the pkt_type byte from skb->data, consuming uninitialized memory. Define VIRTBT_RX_BUF_SIZE once and reuse it in alloc_skb() and sg_init_one(), and gate virtbt_rx_work() on that same constant so the bound checked matches the buffer actually exposed to the device. Reject used.len == 0 in the same gate so an empty completion can no longer reach virtbt_rx_handle(). Use bt_dev_err_ratelimited() because the length value comes from an untrusted backend that can otherwise flood the kernel log. Same class of bug as commit c04db81cd028 ("net/9p: Fix buffer overflow in USB transport layer"), which hardened the USB 9p transport against unchecked device-reported length.

Gravité et risque d'exploitation

CVE-2026-46123 obtient un score CVSS de 7.7/10, 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 3.1 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, 7.0.7, <=7.0.*, <=6.12.*, <e6b4296f170d949ebba937cf6a3f247ec9550d2c, 0, 6.0.8, <4236e55b2d9d1ffd3b4bdf8ebbb86e5a0a526b4a, 9b67438e315b925a699f0178f4a48baf3d2d6ef4, 6.12.88, <b40cdd1b1370d76e9e760af4490cb4a351cceead, 5.15.209, <=6.6.*, 6.1.175, <21bd244b6de5d2fe1063c23acc93fbdd2b20d112, <6c1730099a6fc18b183bd6c1adad3b54adcaeda9, cf2719a21fdb9d4c8e9c834d279163609bef575d, 7.1, <=6.18.*, <fd91fa2678ab603dfb285416c1cf3843d7be1e41, 5.15.78, 6.1, <ed41c81d30b211a671667259c3b5feeba0e062d5, <=*, <5.15.209, <=5.15.*, 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be, 6.6.140, 6.18.30, <6.1) 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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