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UK Cyber Defence
VulnerabilityAwaiting Analysis

CVE-2026-101309

This race condition could be triggered by a guest running malicious, privileged code.

HIGH 7.0EPSS 0.12%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.12%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

The xHCI (USB 3) device model did not validate or save the event ring size provided by the guest. The size was re-read from guest memory on each use, and Transfer Request Block (TRB) fields were loaded without protection against concurrent modification by the guest. This race condition could be triggered by a guest running malicious, privileged code. A malicious guest can crash the bhyve process or potentially execute arbitrary code in the host userspace context running the virtual machine, subject to bhyve's Capsicum sandbox.

CVSS 3.1
7.0 HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS
0.12% probability · 2th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-362
Source
secteam@freebsd.org
EPSS trend
0%3%5%15 October 2026: 0.18%26 October 2026: 0.12%15 October 202626 October 2026

EPSS moved from 0.2% on 15 October 2026 to 0.1% on 26 October 2026.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.