HOMEVULNERABILITIESCVE-2021-4158
MEDIUM

CVE-2021-4158

CWE-476Published: August 24, 2022· Updated: Jun 17, 2026

6.0
CVSS v3.1

Official Description

A NULL pointer dereference issue was found in the ACPI code of QEMU. A malicious, privileged user within the guest could use this flaw to crash the QEMU process on the host, resulting in a denial of service condition.

NVD Source

Technical Analysis

CVE-2021-4158 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 6.0.

The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.

CVSS v3.1 Vector Breakdown

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

Affected Vendors & Products

qemu1 product(s)
qemu
Red Hat1 product(s)
enterprise linux
Source: NVD CPE · 2 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

PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=2035002
PATCHhttps://gitlab.com/qemu-project/qemu/-/commit/9bd6565ccee68f72d5012e24646e12a1c662827e
PATCHhttps://www.mail-archive.com/qemu-devel%40nongnu.org/msg857944.html
PATCHhttps://bugzilla.redhat.com/show_bug.cgi?id=2035002
PATCHhttps://gitlab.com/qemu-project/qemu/-/commit/9bd6565ccee68f72d5012e24646e12a1c662827e
PATCHhttps://www.mail-archive.com/qemu-devel%40nongnu.org/msg857944.html
ADVISORYhttps://access.redhat.com/security/cve/CVE-2021-4158
ADVISORYhttps://gitlab.com/qemu-project/qemu/-/issues/770
ADVISORYhttps://access.redhat.com/security/cve/CVE-2021-4158
ADVISORYhttps://gitlab.com/qemu-project/qemu/-/issues/770

All References (10)

→
https://access.redhat.com/security/cve/CVE-2021-4158Third Party Advisory
→
https://bugzilla.redhat.com/show_bug.cgi?id=2035002Issue Tracking · Patch · Third Party Advisory
→
https://gitlab.com/qemu-project/qemu/-/commit/9bd6565ccee68f72d5012e24646e12a1c662827ePatch · Third Party Advisory
→
https://gitlab.com/qemu-project/qemu/-/issues/770Exploit · Third Party Advisory
→
https://www.mail-archive.com/qemu-devel%40nongnu.org/msg857944.htmlPatch · Third Party Advisory
→
https://access.redhat.com/security/cve/CVE-2021-4158Third Party Advisory
→
https://bugzilla.redhat.com/show_bug.cgi?id=2035002Issue Tracking · Patch · Third Party Advisory
→
https://gitlab.com/qemu-project/qemu/-/commit/9bd6565ccee68f72d5012e24646e12a1c662827ePatch · Third Party Advisory
→
https://gitlab.com/qemu-project/qemu/-/issues/770Exploit · Third Party Advisory
→
https://www.mail-archive.com/qemu-devel%40nongnu.org/msg857944.htmlPatch · Third Party Advisory

Quick Facts

CVE IDCVE-2021-4158
CVSS Score6.0 / 10
SeverityMEDIUM
WeaknessCWE-476
CISA KEVNo
Affected2 vendor(s)
PublishedAug 24, 2022

Related CVEs (CWE-476)

CVE-2010-2495
10.0
CVE-2022-36648
10.0
CVE-2019-10534
9.8
CVE-2019-18190
9.8
CVE-2019-16092
9.8
CVE-2019-17539
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-4158 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.
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