CVE-2021-3607

Host process crash via unchecked ring page count

Published Feb 24, 2022 · Updated Aug 3, 2024

Integer underflow in QEMU's VMware PVRDMA device before 6.1.0 allows privileged guest OS users to crash the host QEMU process. The init_dev_ring function accepts a guest-supplied num_pages value of zero, subtracts one, and passes the wrapped count to pvrdma_ring_init for g_malloc allocation. The PVRDMA device must be present in the build, and privileged guest access is required; exploitation exhausts host memory or dereferences NULL and terminates the virtual machine process.

CVSS severity6.0
Medium
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in QEMU's VMware PVRDMA device before 6.1.0 allows privileged guest OS users to crash the host QEMU process. The init_dev_ring function accepts a guest-supplied num_pages value of zero, subtracts one, and passes the wrapped count to pvrdma_ring_init for g_malloc allocation. The PVRDMA device must be present in the build, and privileged guest access is required; exploitation exhausts host memory or dereferences NULL and terminates the virtual machine process.

The record

CVE
CVE-2021-3607
Published
Feb 24, 2022
Updated
Aug 3, 2024
Vendor
QEMU Project
Product
QEMU
Classifications
CWE-190, CWE-191, T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Feb 24, 2022CVE 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=qemu-kvm 6.1.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

QEMU Project · QEMUversion=qemu-kvm 6.1.0

Published CVSS scores

4.9NIST NVDAV:L/AC:L/Au:N/C:N/I:N/A:C
6.0NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H
6.0Red HatCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H

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-190Integer Overflow or Wraparound
CWE-191Integer Underflow (Wrap or Wraparound)
T1499.004Application or System Exploitation

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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