HOMEVULNERABILITIESCVE-2021-3735
MEDIUM

CVE-2021-3735

CWE-667Published: August 26, 2022· Updated: Jun 17, 2026

4.4
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-3735 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires high privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 4.4.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorLocal
Attack ComplexityLow
Privileges Req.High
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

Debian1 product(s)
debian linux
qemu1 product(s)
qemu
Source: NVD CPE · 3 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://access.redhat.com/security/cve/CVE-2021-3735
ADVISORYhttps://bugzilla.redhat.com/show_bug.cgi?id=1997184
ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2021-3735
ADVISORYhttps://access.redhat.com/security/cve/CVE-2021-3735
ADVISORYhttps://bugzilla.redhat.com/show_bug.cgi?id=1997184
ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2021-3735

All References (7)

→
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/

Quick Facts

CVE IDCVE-2021-3735
CVSS Score4.4 / 10
SeverityMEDIUM
WeaknessCWE-667
CISA KEVNo
Affected2 vendor(s)
PublishedAug 26, 2022

Related CVEs (CWE-667)

CVE-2021-22530
9.9
CVE-2019-5886
9.8
CVE-2020-12658
9.8
CVE-2020-15674
8.8
CVE-2024-58087
8.1
CVE-2020-0420
7.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-3735 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
← All Vulnerabilities·Search for CVE-2021-3735·NVD