CVE-2020-3946Network attack vector

AutoUpdate crash via recursive XML entity expansion

Published Apr 20, 2020 · Updated Aug 4, 2024

XML entity expansion in VMware InstallBuilder before 19.11.0 allows attackers to crash AutoUpdate or an update-checking installer via update.xml. The update.xml parser loads a remote XML document into memory without restricting recursive entity expansion, causing memory consumption until the process crashes. Exploitation requires control of the update server, DNS impersonation of that server, or local modification of the updates.ini URL; the reported consequence is process termination from memory exhaustion.

CVSS severity7.5
High
EPSS probability1.04%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

XML entity expansion in VMware InstallBuilder before 19.11.0 allows attackers to crash AutoUpdate or an update-checking installer via update.xml. The update.xml parser loads a remote XML document into memory without restricting recursive entity expansion, causing memory consumption until the process crashes. Exploitation requires control of the update server, DNS impersonation of that server, or local modification of the updates.ini URL; the reported consequence is process termination from memory exhaustion.

The record

CVE
CVE-2020-3946
Published
Apr 20, 2020
Updated
Aug 4, 2024
Vendor
VMware
Product
InstallBuilder
Classifications
CWE-776, CAPEC-197, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 20, 2020CVE 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=All versions prior to version 19.11.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

VMware · InstallBuilderversion=All versions prior to version 19.11.0

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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.

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

No observations available

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

Weakness, pattern, technique

CWE-776Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')
CAPEC-197Exponential Data Expansion
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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