CVE-2021-29631

Name: CVE-2021-29631
Creator: NVD / NIST
Published: 2021-08-30T18:15:08.923+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.8/10EPSS 0.29%

Last modified Jun 17, 2026

CVE-2021-29631 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. In FreeBSD 13.0-STABLE before n246941-20f96f215562, 12.2-STABLE before r370400, 11.4-STABLE before r370399, 13.0-RELEASE before p4, 12.2-RELEASE before p10, and 11.4-RELEASE before p13, certain VirtIO-based device models in bhyve failed to handle errors when fetching I/O descriptors. A malicious guest may cause the device model to operate on uninitialized I/O vectors leading to memory corruption, crashing of the bhyve process, and possibly arbitrary code execution in the bhyve process.. EPSS estimates a 0.29% chance of exploitation in the next 30 days.

Description

In FreeBSD 13.0-STABLE before n246941-20f96f215562, 12.2-STABLE before r370400, 11.4-STABLE before r370399, 13.0-RELEASE before p4, 12.2-RELEASE before p10, and 11.4-RELEASE before p13, certain VirtIO-based device models in bhyve failed to handle errors when fetching I/O descriptors. A malicious guest may cause the device model to operate on uninitialized I/O vectors leading to memory corruption, crashing of the bhyve process, and possibly arbitrary code execution in the bhyve process.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.29%

20.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-908

Affected Software

Vendor	Product	Versions
Freebsd	Freebsd	11.4
Freebsd	Freebsd	12.2
Freebsd	Freebsd	13.0

References

https://security.FreeBSD.org/advisories/FreeBSD-SA-21:13.bhyve.ascVendor Advisory
https://security.netapp.com/advisory/ntap-20210923-0004/Third Party Advisory
https://security.FreeBSD.org/advisories/FreeBSD-SA-21:13.bhyve.ascVendor Advisory
https://security.netapp.com/advisory/ntap-20210923-0004/Third Party Advisory

Timeline

Published: Aug 30, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-29631?

How severe is CVE-2021-29631?

CVE-2021-29631 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.29% probability of exploitation in the next 30 days.

How do I fix CVE-2021-29631?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-29631?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST