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NetbeansApplication · Apache

CVE-2018-17191

CRITICAL · 9.8 CVSS v3.0 Published 2018-12-31
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Apache NetBeans (incubating) 9.0 NetBeans Proxy Auto-Configuration (PAC) interpretation is vulnerable for remote command execution (RCE). Using the nashorn script engine the environment of the javascript execution for the Proxy Auto-Configuration leaks privileged objects, that can be used to circumvent the execution limits. If a different script engine was used, no execution limits were in place. Both vectors allow remote code execution.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Apache NetBeans 9.0 has a critical RCE vulnerability in its Proxy Auto-Configuration (PAC) file interpreter. The nashorn JavaScript engine used for PAC evaluation exposes privileged objects that can be leveraged to execute arbitrary code. Additionally, alternative script engines have no execution sandboxing, providing a second RCE vector.

MitigationUpgrade to Apache NetBeans 10.0 or later which contains the security fix, or avoid using PAC configurations until the upgrade can be performed.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
NetbeansApplication
Affected:= 9.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed NetBeans version
    Check the About or Help menu in NetBeans, or look for version info in the installation directory. On Windows, check the program files folder. On Linux/Mac, check /opt/netbeans or ~/netbeans
    Affected if The version is exactly 9.0 (other versions like 8.x or 10.0+ are not affected)
  2. Determine if PAC is configured
    Look in NetBeans preferences under Options > General > Proxy Settings, or check for PAC (Proxy Auto-Configuration) URL or script path configured in the IDE network settings
    Affected if A PAC script URL or file path is configured and in use by NetBeans
  3. Inspect the PAC script source
    If a PAC file is in use, locate and examine it. Check if the script uses JavaScript (nashorn engine) or alternative scripting languages like BeanShell, Groovy, or other JVM script engines
    Affected if The PAC configuration loads a custom script that could expose privileged Java objects or run unsandboxed code
  4. Check for custom proxy scripts
    Review any .js, .bsh, .groovy, or other script files used for proxy configuration in the NetBeans config directories
    Affected if Custom scripts are present that leverage the NetBeans script engine for PAC evaluation

You are affected only if you have Apache NetBeans version 9.0 specifically AND have a PAC proxy configuration enabled that evaluates scripts using the nashorn engine or alternative unsandboxed script engines.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Apache NetBeans 10.0 or later which contains the security fix, or avoid using PAC configurations until the upgrade can be performed.

Recommended fix Moderate confidence

Apache NetBeans 10.0 or later (latest stable release recommended)

  1. 1. Back up your current NetBeans configuration and projects
  2. 2. Uninstall Apache NetBeans 9.0
  3. 3. Download Apache NetBeans 10.0 or later from the official Apache NetBeans download page (https://netbeans.apache.org/)
  4. 4. Install the newer version following the standard installation procedure
  5. 5. Reconfigure your Proxy Auto-Configuration (PAC) settings if needed after upgrade
  6. 6. Verify that PAC functionality works correctly with the new installation
Caveat Minor - some plugin compatibility may need verification; workspace/project configuration migration recommended

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Netbeans Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-17191 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data