CVE-2021-32846
Moby HyperKit uninitialized memory use in virtio-sock pci_vtsock_proc_tx
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
7.7
Moby HyperKit uninitialized memory use in virtio-sock pci_vtsock_proc_tx
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.
- Record
CVE-2021-32846- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H - Weakness
- CWE-908
- Updated
- 2026-11-02
EUVDEUVD-2021-19578
7.7
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.
- Record
EUVD-2021-19578- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-8j79-g729-4vv7
7.8
HyperKit is a toolkit for embedding hypervisor capabilities in an application. In versions 0...
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.
- Record
GHSA-8j79-g729-4vv7- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-754, CWE-908
- Updated
- 2026-11-02
NVD
7.7
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.
- Record
CVE-2021-32846- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H - CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-908, CWE-754
- Updated
- 2026-11-02
OSV
7.8
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.
- Record
CVE-2021-32846- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-32846 is a high vulnerability (CVSS 7.7) in Moby Hyperkit, published February 17, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.32%, the 24th percentile. No source names a fixed version.