{"id":"CVE-2021-32846","aliases":["EUVD-2021-19578","GHSA-8j79-g729-4vv7"],"status":"published","title":"Moby HyperKit uninitialized memory use in virtio-sock pci_vtsock_proc_tx","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.","severity":{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00317,"percentile":0.24973,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-754","CWE-908"],"published":"2023-02-17T00:00:00Z","modified":"2026-10-20T14:05:11Z","products":[{"vendor":"moby","product":"hyperkit"},{"vendor":"mobyproject","product":"hyperkit"}],"references":[{"url":"https://securitylab.github.com/advisories/GHSL-2021-054_057-moby-hyperkit/","tags":["x_transferred","Third Party Advisory","advisory"]},{"url":"https://github.com/moby/hyperkit/pull/313","tags":["x_transferred","Patch","fix"]},{"url":"https://github.com/moby/hyperkit/commit/af5eba2360a7351c08dfd9767d9be863a50ebaba","tags":["x_transferred","Patch","fix"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-32846"},{"url":"https://github.com/advisories/GHSA-8j79-g729-4vv7"}],"sources":{"cve":[{"id":"CVE-2021-32846","title":"Moby HyperKit uninitialized memory use in virtio-sock pci_vtsock_proc_tx","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.","status":"published","published":"2023-02-17T00:00:00Z","modified":"2025-03-10T21:09:47.105Z","cvss":[{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-908"],"updated_at":"2026-11-02T14:33:07.014772Z"}],"euvd":[{"id":"EUVD-2021-19578","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.","status":"published","published":"2023-02-17T00:00:00Z","modified":"2025-03-10T21:09:47Z","cvss":[{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T20:53:09.197707Z"}],"ghsa":[{"id":"GHSA-8j79-g729-4vv7","title":"HyperKit is a toolkit for embedding hypervisor capabilities in an application. In versions 0...","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.","status":"published","published":"2023-02-18T00:31:58Z","modified":"2023-07-04T05:01:44Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-754","CWE-908"],"updated_at":"2026-11-02T14:54:40.485503Z"}],"nvd":[{"id":"CVE-2021-32846","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.","status":"published","published":"2023-02-17T23:15:12.037Z","modified":"2026-06-17T03:53:44.99Z","cvss":[{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"high","assessor":"secondary"},{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-908","CWE-754"],"updated_at":"2026-11-02T14:07:07.323379Z"}],"osv":[{"id":"CVE-2021-32846","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.","status":"published","published":"2023-02-17T23:15:12.037Z","modified":"2026-10-20T14:05:11.52706667Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T15:44:19.793849Z"}]}}