CVE-2026-46123
published 2026-05-28CVE-2026-46123: 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…
high7.7CVSS 3.1
AVLACLPRNUINSUCHINAH
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.
Affected
12 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| linux | linux | — | — |
| linux | linux | — | — |
| linux | linux | >= 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be < fd91fa2678ab603dfb285416c1cf3843d7be1e41 | fd91fa2678ab603dfb285416c1cf3843d7be1e41 |
| linux | linux | >= 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be < ed41c81d30b211a671667259c3b5feeba0e062d5 | ed41c81d30b211a671667259c3b5feeba0e062d5 |
| linux | linux | >= 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be < 6c1730099a6fc18b183bd6c1adad3b54adcaeda9 | 6c1730099a6fc18b183bd6c1adad3b54adcaeda9 |
| linux | linux | >= 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be < b40cdd1b1370d76e9e760af4490cb4a351cceead | b40cdd1b1370d76e9e760af4490cb4a351cceead |
| linux | linux | >= 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be < e6b4296f170d949ebba937cf6a3f247ec9550d2c | e6b4296f170d949ebba937cf6a3f247ec9550d2c |
| linux | linux | >= 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be < 21bd244b6de5d2fe1063c23acc93fbdd2b20d112 | 21bd244b6de5d2fe1063c23acc93fbdd2b20d112 |
| linux | linux | >= 5.15.78 < 5.15.209 | 5.15.209 |
| linux | linux | >= 6.0.8 < 6.1 | 6.1 |
| linux | linux | >= cf2719a21fdb9d4c8e9c834d279163609bef575d < 4236e55b2d9d1ffd3b4bdf8ebbb86e5a0a526b4a | 4236e55b2d9d1ffd3b4bdf8ebbb86e5a0a526b4a |
| linux | linux_kernel | — | — |