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CVE-2021-32846

Moby HyperKit uninitialized memory use in virtio-sock pci_vtsock_proc_tx

7.7 High

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

0.32%Down 0.6 points since Feb 18, 2023
90%50%10%1%

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 HighCVSS: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 HighCVSS: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 HighCVSS: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 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CVSS 3.1
7.8 HighCVSS: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 HighCVSS: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

History
RecordedChangedSources
first indexedCVE 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.

References

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