CVE-2021-3735

Name: CVE-2021-3735
Creator: NVD / NIST
Published: 2022-08-26T16:15:09.467+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.4/10EPSS 0.19%

Last modified Jun 17, 2026

CVE-2021-3735 is a medium-severity vulnerability rated 4.4/10 on the CVSS scale. A deadlock issue was found in the AHCI controller device of QEMU. It occurs on a software reset (ahci_reset_port) while handling a host-to-device Register FIS (Frame Information Structure) packet from the guest. EPSS estimates a 0.19% chance of exploitation in the next 30 days.

Description

A deadlock issue was found in the AHCI controller device of QEMU. It occurs on a software reset (ahci_reset_port) while handling a host-to-device Register FIS (Frame Information Structure) packet from the guest. A privileged user inside the guest could use this flaw to hang the QEMU process on the host, resulting in a denial of service condition. The highest threat from this vulnerability is to system availability.

Metrics

CVSS 3.1

4.4/10

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

EPSS Probability

0.19%

8.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Qemu	Qemu	6.1.0	Rc4
Debian	Debian Linux	10.0	—
Debian	Debian Linux	11.0	—

References

https://access.redhat.com/security/cve/CVE-2021-3735Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1997184Issue Tracking, Third Party Advisory
https://security-tracker.debian.org/tracker/CVE-2021-3735Third Party Advisory
https://access.redhat.com/security/cve/CVE-2021-3735Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1997184Issue Tracking, Third Party Advisory
https://security-tracker.debian.org/tracker/CVE-2021-3735Third Party Advisory
https://security.netapp.com/advisory/ntap-20250228-0009/

Timeline

Published: Aug 26, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3735?

How severe is CVE-2021-3735?

CVE-2021-3735 has a CVSS score of 4.4/10 (MEDIUM severity). The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3735?

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-2021-3735?

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

Scan your code now

Source: NVD / NIST