What’s Vulnerable › Vulnerabilities

CVE-2021-32846: Moby HyperKit uninitialized memory use in virtio-sock pci_vtsock_proc_tx

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-02-17 · updated 2026-06-17
• Weakness: CWE-908

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.

Affected products

• moby hyperkit: through 0.20210107

References

• https://github.com/moby/hyperkit/commit/af5eba2360a7351c08dfd9767d9be863a50ebaba
• https://github.com/moby/hyperkit/pull/313
• https://securitylab.github.com/advisories/GHSL-2021-054_057-moby-hyperkit/
• https://github.com/moby/hyperkit/commit/af5eba2360a7351c08dfd9767d9be863a50ebaba
• https://github.com/moby/hyperkit/pull/313
• https://securitylab.github.com/advisories/GHSL-2021-054_057-moby-hyperkit/

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