CVE-2020-27661

Guest-triggered process crash via zero packet size

Published Jun 2, 2021 · Updated Aug 4, 2024

Divide by zero in QEMU 5.1.0 through 5.1.1 allows guest OS users to crash the host QEMU process through DWC2 USB emulation. The dwc2_handle_packet function reads guest-controlled HCCHAR_MPS as the maximum packet size and uses a zero value as a divisor without validation. A guest must access an emulated DWC2 controller; triggering the flaw terminates the associated QEMU process and interrupts that virtual machine.

CVSS severity6.5
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Divide by zero in QEMU 5.1.0 through 5.1.1 allows guest OS users to crash the host QEMU process through DWC2 USB emulation. The dwc2_handle_packet function reads guest-controlled HCCHAR_MPS as the maximum packet size and uses a zero value as a divisor without validation. A guest must access an emulated DWC2 controller; triggering the flaw terminates the associated QEMU process and interrupts that virtual machine.

The record

CVE
CVE-2020-27661
Published
Jun 2, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-369, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 2, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
2.1NVDAV: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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-369Divide By Zero
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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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