CVE-2020-35505Public exploit

Guest-triggered host process crash via unchecked SCSI state

Published May 28, 2021 · Updated Aug 4, 2024

NULL pointer dereference in QEMU before 6.0.0 allows privileged guest OS users to crash the host QEMU process via a SCSI command. The do_busid_cmd function reads current_dev->id without confirming that current_dev is valid when Transfer Information follows no select command. Exploitation requires control of a privileged guest configured with am53c974 emulation, and the bounded consequence is interruption of that guest's QEMU process.

CVSS severity4.4
Medium
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in QEMU before 6.0.0 allows privileged guest OS users to crash the host QEMU process via a SCSI command. The do_busid_cmd function reads current_dev->id without confirming that current_dev is valid when Transfer Information follows no select command. Exploitation requires control of a privileged guest configured with am53c974 emulation, and the bounded consequence is interruption of that guest's QEMU process.

The record

CVE
CVE-2020-35505
Published
May 28, 2021
Updated
Aug 4, 2024
Vendor
QEMU Project
Product
QEMU
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. May 28, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=qemu 6.0.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

QEMU Project · QEMUversion=qemu 6.0.0

Published CVSS scores

4.4NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
2.1NIST NVDAV:L/AC:L/Au:N/C:N/I:N/A:P

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 exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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