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.
Conclusion & alert: CVE-2021-32846 is rated Low Risk (39.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.32%).Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
Exploit prediction scoring system (EPSS) score for CVE-2021-32846
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).