CVE-2021-3392

Host process crash via stale SCSI request

Published Mar 23, 2021 · Updated Aug 3, 2024

Use-after-free in QEMU 2.10.0 through 5.2.0 allows guest OS users with elevated privileges to crash the host QEMU process. On an SCSI I/O error, mptsas_free_request() frees a request without removing it from the MegaRAID emulator's pending queue, which later reuses the stale entry. Exploitation requires control of a privileged guest, and the bounded consequence is interruption of that guest's QEMU process.

CVSS severity3.2
Low
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in QEMU 2.10.0 through 5.2.0 allows guest OS users with elevated privileges to crash the host QEMU process. On an SCSI I/O error, mptsas_free_request() frees a request without removing it from the MegaRAID emulator's pending queue, which later reuses the stale entry. Exploitation requires control of a privileged guest, and the bounded consequence is interruption of that guest's QEMU process.

The record

CVE
CVE-2021-3392
Published
Mar 23, 2021
Updated
Aug 3, 2024
Vendor
QEMU Project
Product
QEMU
Classifications
CWE-416, T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Mar 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=between 2.10.0 and 5.2.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

QEMU Project · QEMUversion=between 2.10.0 and 5.2.0

Published CVSS scores

3.2OracleCVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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