CVE-2026-46123

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine without logging in. High risk of data exposure, service disruption.

Exploit odds

0.1% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-28 10:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-24 16:51 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.1% in the next 30 days (EPSS).
• Severity: 7.7 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-05-28 10:16 UTC

Last modified

2026-06-24 16:51 UTC

Exploit probability

0.1% · EPSS, next 30 days

Weakness

CWE-787 · Out-of-bounds write

Record status

Undergoing Analysis

Affected

• Linux Kernel < 5.15.209
• Linux Kernel < 6.1
• Linux Kernel < 6.1.175
• Linux Kernel < 6.6.140
• Linux Kernel < 6.12.88
• Linux Kernel < 6.18.30
• Linux Kernel < 7.0.7
• Linux Kernel 6.1

Attack profile CVSS 3.1 · 7.7

Attack vector

Local

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-46123.md and follow it. Check whether this project is affected by CVE-2026-46123. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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