CVE-2026-46186
Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: virtio_bt: validate rx pkt_type header length virtbt_rx_handle() reads the leading pkt_type byte from the RX skb and forwards the remainder to hci_recv_frame() for every event/ACL/SCO/ISO type, without checking that the remaining payload is at least the fixed HCI header for that type. After the preceding patch bounds the backend-supplied used.len to [1, VIRTBT_RX_BUF_SIZE], a one-byte completion still reaches hci_recv_frame() with skb->len already pulled to 0. If the byte happened to be HCI_ACLDATA_PKT, the ACL-vs-ISO classification fast-path in hci_dev_classify_pkt_type() dereferences hci_acl_hdr(skb)->handle whenever the HCI device has an active CIS_LINK, BIS_LINK, or PA_LINK connection, reading two bytes of uninitialized RX-buffer data. The same hazard exists for every packet type the driver accepts because none of the switch cases in virtbt_rx_handle() check skb->len against the per-type minimum HCI header size before handing the frame to the core. After stripping pkt_type, require skb->len to cover the fixed header size for the selected type (event 2, ACL 4, SCO 3, ISO 4) before calling hci_recv_frame(); drop ratelimited otherwise. Unknown pkt_type values still take the original kfree_skb() default path. Use bt_dev_err_ratelimited() because both the length and pkt_type values come from an untrusted backend that can otherwise flood the kernel log.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| debian | bookworm | affected | |
| debian | bullseye | fixed | 0 |
| debian | forky | fixed | 7.0.7-1 |
| debian | sid | fixed | 7.0.7-1 |
| debian | trixie | fixed | 6.12.88-1 |
| sles | affected | |
References
- https://git.kernel.org/stable/c/1e1e509b6fd2a42421745bbcd98bd16daad20904
- https://git.kernel.org/stable/c/2c1143564c71e7497b42d8360a8379ccbb011d3c
- https://git.kernel.org/stable/c/3485c7236c59c8c34a41af1c4b52982437554e79
- https://git.kernel.org/stable/c/daf23014e5d975e72ea9c02b5160d3fcf070ea47
- https://git.kernel.org/stable/c/f743eab6486965f276c7e3f1700895f014fdc6db
- https://security-tracker.debian.org/tracker/CVE-2026-46186
- https://www.suse.com/security/cve/CVE-2026-46186.html
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.