CVE-2020-5529Network attack vector

Remote code execution via Rhino Java access

Published Feb 11, 2020 · Updated Oct 15, 2024

Code injection in HtmlUnit prior to 2.37.0 allows remote attackers to execute arbitrary Java code via malicious JavaScript evaluated by Rhino. Improper Rhino initialization exposes Java objects and resources, including Java method access, to script supplied through fetched web content. The attack requires the application to automatically evaluate attacker-controlled content, such as content delivered through a man-in-the-middle position; Android embeddings are additionally affected by platform-specific initialization.

CVSS severity8.1
High
EPSS probability4.72%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in HtmlUnit prior to 2.37.0 allows remote attackers to execute arbitrary Java code via malicious JavaScript evaluated by Rhino. Improper Rhino initialization exposes Java objects and resources, including Java method access, to script supplied through fetched web content. The attack requires the application to automatically evaluate attacker-controlled content, such as content delivered through a man-in-the-middle position; Android embeddings are additionally affected by platform-specific initialization.

The record

CVE
CVE-2020-5529
Published
Feb 11, 2020
Updated
Oct 15, 2024
Vendor
HtmlUnit
Product
HtmlUnit
Classifications
CWE-94, CWE-665, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 11, 2020CVE publishedPublication date reported by the CVE source.
  2. Oct 15, 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=prior to 2.37.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

HtmlUnit · HtmlUnitversion=prior to 2.37.0

Published CVSS scores

5.6JPCERT/CC JVNCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
5.1JPCERT/CC JVNAV:N/AC:H/Au:N/C:P/I:P/A:P
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
8.1NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
CWE-665Improper Initialization
T1059.007Command and Scripting Interpreter: JavaScript

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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