CVE-2021-32845 | Moby HyperKit uninitialized memory use vtrnd pci_vtrnd_notify

HyperKit is a toolkit for embedding hypervisor capabilities in an application. In versions 0.20210107 and prior of HyperKit, the implementation of `qnotify` at `pci_vtrnd_notify` fails to check the return value of `vq_getchain`. This leads to `struct iovec iov;` being uninitialized and used to read memory in `len = (int) read(sc->vrsc_fd, iov.iov_base, iov.iov_len);` when an attacker is able to make `vq_getchain` fail. 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 41272a980197917df8e58ff90642d14dec8fe948.

Published: 2023-02-17 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-32845 is rated Low Risk (36.6/100): CVSS High severity, with low exploitation likelihood (EPSS 0.25%). 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-2021-32845

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.07% 0.25% +0.18%
2 2026-03-02 0.18% 0.07% -0.11%
3 2026-02-24 — 0.18% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-32845

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.7 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.5 5.2 [email protected]
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]

Weakness enumeration for CVE-2021-32845

Affected software / configurations for CVE-2021-32845

Vendor Product Version Raw CPE
mobyproject hyperkit <= 0.20210107 cpe:2.3:a:mobyproject:hyperkit:*:*:*:*:*:*:*:*

References for CVE-2021-32845

cvelogic Threat Intelligence