CVE-2023-3494 bhyve privileged guest escape via fwctl
A privileged guest VM can exploit a buffer overflow in the bhyve fwctl driver to execute arbitrary code on the host, potentially bypassing Capsicum sandboxing.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2023-3494?
CVE-2023-3494 is a high-severity memory corruption vulnerability in Freebsd Freebsd, published on 1 Aug 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-120
Which versions are affected by CVE-2023-3494?
It affects 1 product.
Products include Freebsd Freebsd.
How do I fix CVE-2023-3494?
No fix has been published for CVE-2023-3494 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2023-3494 being exploited?
There is no known exploitation of CVE-2023-3494 in the wild and no public exploit code.
Other vulnerabilities in Freebsd Freebsd
Sources
Also known as GHSA-6672-m2hq-hwm4.