CVE-2021-32846 Moby HyperKit uninitialized memory use in virtio-sock pci_vtsock_proc_tx
A guest VM can crash the host or potentially execute code via uninitialized memory use in HyperKit's virtio-sock implementation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2021-32846?
CVE-2021-32846 is a high-severity memory corruption vulnerability in moby hyperkit, published on 17 Feb 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
HyperKit is a toolkit for embedding hypervisor capabilities in an application. In versions 0.20210107, function `pci_vtsock_proc_tx` in `virtio-sock` can lead to to uninitialized memory use. In this situation, there is a check for the return value to be less or equal to `VTSOCK_MAXSEGS`, but that check is not sufficient because the function can return `-1` if it finds an error it cannot recover from. Moreover, the negative return value will be used by `iovec_pull` in a while condition that can further lead to more corruption because the function is not designed to handle a negative `iov_len`. This issue may lead to a guest crashing the host causing a denial of service and, under certain circumstance, memory corruption. This issue is fixed in commit af5eba2360a7351c08dfd9767d9be863a50ebaba.
Which versions are affected by CVE-2021-32846?
It affects 1 product.
Products include Mobyproject Hyperkit.
How do I fix CVE-2021-32846?
No fix has been published for CVE-2021-32846 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-2021-32846 being exploited?
There is no known exploitation of CVE-2021-32846 in the wild and no public exploit code.
Other vulnerabilities in moby hyperkit
Sources
Also known as GHSA-8j79-g729-4vv7.