CVE-2019-20485

Guest API blockage via retained monitor job

Published Mar 19, 2020 · Updated Aug 5, 2024

Denial of service in libvirt before 6.0.0 allows guest OS users to block libvirtd operations for a guest through its agent. The QEMU driver retains the guest's monitor job while waiting for an agent query, so a nonresponsive malicious agent prevents competing monitor work from proceeding. A guest administrator must control or stall the configured guest agent; the bounded consequence is API blockage for operations involving that guest.

CVSS severity5.7
Medium
EPSS probability0.81%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Denial of service in libvirt before 6.0.0 allows guest OS users to block libvirtd operations for a guest through its agent. The QEMU driver retains the guest's monitor job while waiting for an agent query, so a nonresponsive malicious agent prevents competing monitor work from proceeding. A guest administrator must control or stall the configured guest agent; the bounded consequence is API blockage for operations involving that guest.

The record

CVE
CVE-2019-20485
Published
Mar 19, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-20, T1499
Attack vector
adjacent
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 19, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.7NVDCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.7SUSECVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
2.7NVDAV:A/AC:L/Au:S/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499Endpoint Denial of Service

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo