Bluetooth: virtio_bt: clamp rx length before skb_put

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Summary

CVECVE-2026-46123
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-28 10:16:27 UTC
Updated2026-05-28 13:44:01 UTC
DescriptionIn 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.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be ed41c81d30b211a671667259c3b5feeba0e062d5 git Not specified
CNA Linux Linux affected 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be 6c1730099a6fc18b183bd6c1adad3b54adcaeda9 git Not specified
CNA Linux Linux affected 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be b40cdd1b1370d76e9e760af4490cb4a351cceead git Not specified
CNA Linux Linux affected 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be e6b4296f170d949ebba937cf6a3f247ec9550d2c git Not specified
CNA Linux Linux affected 160fbcf3bfb93c3c086427f9f4c8bc70f217e9be 21bd244b6de5d2fe1063c23acc93fbdd2b20d112 git Not specified
CNA Linux Linux affected cf2719a21fdb9d4c8e9c834d279163609bef575d git Not specified
CNA Linux Linux affected 9b67438e315b925a699f0178f4a48baf3d2d6ef4 git Not specified
CNA Linux Linux affected 5.15.78 5.16 semver Not specified
CNA Linux Linux affected 6.0.8 6.1 semver Not specified
CNA Linux Linux affected 6.1 Not specified
CNA Linux Linux unaffected 6.1 semver Not specified
CNA Linux Linux unaffected 6.6.140 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.88 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.30 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.7 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1-rc3 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/ed41c81d30b211a671667259c3b5feeba0e062d5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e6b4296f170d949ebba937cf6a3f247ec9550d2c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b40cdd1b1370d76e9e760af4490cb4a351cceead 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/21bd244b6de5d2fe1063c23acc93fbdd2b20d112 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6c1730099a6fc18b183bd6c1adad3b54adcaeda9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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