CVE-2023-3494

What it is

The fwctl driver implements a state machine which is executed when a bhyve guest accesses certain x86 I/O ports. The interface lets the guest copy a string into a buffer resident in the bhyve process' memory. A bug in the state machine implementation can result in a buffer overflowing when copying this string. Malicious, privileged software running in a guest VM can exploit the buffer overflow to achieve code execution on the host in the bhyve userspace process, which typically runs as root, mitigated by the capabilities assigned through the Capsicum sandbox available to the bhyve process.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

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

Timeline

1. 2023-08-01 23:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 06:14 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: 8.8 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-08-01 23:15 UTC

Last modified

2026-06-17 06:14 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-120 · Classic buffer overflow

Record status

Modified

Affected

• Freebsd 13.1
• Freebsd 13.2

Attack profile CVSS 3.1 · 8.8

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

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-2023-3494.md and follow it. Check whether this project is affected by CVE-2023-3494. 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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