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GraalvmApplication · Oracle

CVE-2026-21933

MEDIUM · 6.1 CVSS v3.1 Published 2026-01-20
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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
Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: Networking). Supported versions that are affected are Oracle Java SE: 8u471, 8u471-b50, 8u471-perf, 11.0.29, 17.0.17, 21.0.9, 25.0.1; Oracle GraalVM for JDK: 17.0.17 and 21.0.9; Oracle GraalVM Enterprise Edition: 21.3.16. Easily exploitable vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition. Successful attacks require human interaction from a person other than the attacker and while the vulnerability is in Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition, attacks may significantly impact additional products (scope change). Successful attacks of this vulnerability can result in unauthorized update, insert or delete access to some of Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition accessible data as well as unauthorized read access to a subset of Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition accessible data. Note: This vulnerability can be exploited by using APIs in the specified Component, e.g., through a web service which supplies data to the APIs. This vulnerability also applies to Java deployments, typically in clients running sandboxed Java Web Start applications or sandboxed Java applets, that load and run untrusted code (e.g., code that comes from the internet) and rely on the Java sandbox for security. CVSS 3.1 Base Score 6.1 (Confidentiality and Integrity impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).

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 · moderate confidence

Networking vulnerability in Oracle Java SE and GraalVM allowing unauthenticated remote attackers with network access to compromise the application through APIs, potentially achieving unauthorized read and write access to a subset of accessible data. Exploitation requires human interaction and may impact additional products beyond the Java component.

MitigationApply Oracle Critical Patch Update (CPU) for the affected Java SE and GraalVM versions. Review and restrict API access where possible, and ensure Java sandbox configurations for applet/Web Start deployments.

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
GraalvmApplication
Affected:= 21.3.16
Graalvm For JdkApplication
Affected:= 17.0.17= 21.0.9
JdkApplication
Affected:= 1.8.0= 11.0.29= 17.0.17= 21.0.9= 25.0.1
JreApplication
Affected:= 1.8.0= 11.0.29= 17.0.17= 21.0.9= 25.0.1

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
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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 Java/JRE/JDK version
    Run 'java -version' or 'java -fullversion' from the command line to obtain the exact version string
    Affected if The reported version matches any of the affected versions: 1.8.0, 11.0.29, 17.0.17, 21.0.9, or 25.0.1
  2. Identify installed GraalVM version
    Run 'java -version' or check the GraalVM installation directory if using GraalVM specifically; look for version strings like 21.3.16, 17.0.17, or 21.0.9
    Affected if The installed GraalVM version is 21.3.16, or GraalVM for JDK versions 17.0.17 or 21.0.9
  3. Verify if Java network APIs are exposed
    Review application network configuration and exposed endpoints; check if the Java application listens on network ports accessible from untrusted sources
    Affected if Java-based network services or APIs are accessible over the network without proper access controls
  4. Check for unauthenticated network access
    Audit firewall rules, network ACLs, and application authentication settings for Java network endpoints; verify whether network-accessible Java APIs require authentication
    Affected if Java network APIs are reachable without authentication from untrusted network segments or the public internet
  5. Confirm human interaction requirement
    Review whether the vulnerable Java code paths are triggered by client-side operations such as applet interactions, Web Start deployments, or other user-initiated network requests
    Affected if The deployment involves applet/Web Start functionality or other scenarios where untrusted clients can invoke Java APIs over the network

You are affected if you are running any of the listed Oracle JDK, JRE, or GraalVM versions AND your Java APIs are exposed over the network to untrusted clients or users.

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

Apply Oracle Critical Patch Update (CPU) for the affected Java SE and GraalVM versions. Review and restrict API access where possible, and ensure Java sandbox configurations for applet/Web Start deployments.

Recommended fix Moderate confidence

Upgrade to the next available Oracle Critical Patch Update (CPU) for your respective version line: JDK 8u481+, JDK 11.0.25+, JDK 17.0.25+, JDK 21.0.5+, or JDK 25.0.2+; GraalVM for JDK 17.0.25+ or 21.0.5+; GraalVM Enterprise Edition 21.3.17+

  1. 1. Identify the Oracle Java SE / GraalVM version currently installed by running 'java -version'
  2. 2. Determine the appropriate upgrade path based on your current version (see upgrade_path)
  3. 3. Download the latest Oracle JDK or GraalVM from the official Oracle download page: https://www.oracle.com/java/technologies/downloads/
  4. 4. Install the new version following Oracle's installation instructions
  5. 5. Update JAVA_HOME environment variable to point to the new installation directory
  6. 6. Verify the new version is active by running 'java -version'
  7. 7. Test your applications to ensure compatibility with the upgraded JDK
Caveat Oracle Critical Patch Updates are generally backward-compatible; however, regression testing is recommended to ensure existing functionality is preserved

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

Fix this in Graalvm Scoped from the published advisory
  • Consultation3.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
19.0 hours of engineering $3,300
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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-2026-21933 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