CVE-2021-32846: moby hyperkit Use of Uninitialized Resource

Vulnerability summary

CVE-2021-32846 is a high (CVSS 7.8) Use of Uninitialized Resource vulnerability in moby hyperkit. EPSS estimates a 0.32% chance of exploitation in the next 30 days, higher than 23.2% of scored vulnerabilities.

Timeline

1. 17-02-2023
   PublishedVulnerability first disclosed.
2. 10-03-2025
   Last modifiedVulnerability information updated.

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.

• CWE-908Use of Uninitialized ResourceThe product uses or accesses a resource that has not been initialized.
• CWE-754Improper Check for Unusual or Exceptional ConditionsThe product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.