CVE-2019-17639
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 · uneditedIn Eclipse OpenJ9 prior to version 0.21 on Power platforms, calling the System.arraycopy method with a length longer than the length of the source or destination array can, in certain specially crafted code patterns, cause the current method to return prematurely with an undefined return value. This allows whatever value happens to be in the return register at that time to be used as if it matches the method's declared return type.
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 confidenceIn Eclipse OpenJ9 prior to version 0.21 on Power platforms, the System.arraycopy method has a flaw where calling it with a length parameter exceeding the source or destination array length can cause premature method return with an undefined value from the return register, leading to potential type confusion and data corruption.
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<= 0.20.0= 0.21.0CVSS 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
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify the system architectureRun 'uname -m' or 'arch' on Linux/AIX to confirm the processor type. On Power systems, this typically shows 'ppc64', 'ppc64le', or 'powerpc64'.Affected if The system is NOT running on Power architecture (ppc64/ppc64le/powerpc64)
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Identify the JVM vendorRun 'java -version' and examine the output. Eclipse OpenJ9 typically displays 'Eclipse OpenJ9' in the version string.Affected if The JVM is NOT Eclipse OpenJ9 (for example, if using HotSpot, Oracle JRockit, or other implementations)
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Check the Eclipse OpenJ9 versionRun 'java -version' and extract the version number. OpenJ9 versions follow the pattern 0.x.x (for example, 0.20.0, 0.21.0). Compare your version against the affected range: versions <= 0.20.0 or exactly 0.21.0.Affected if The OpenJ9 version is greater than 0.21.0 (for example, 0.22.0 or later)
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Verify the vulnerable code path existsReview Java application source code for calls to System.arraycopy where the length parameter could exceed source or destination array lengths at runtime. Search for patterns like System.arraycopy(src, 0, dst, 0, len) where 'len' comes from untrusted or computed values.Affected if Application code makes System.arraycopy calls with length parameters that could exceed array bounds
You are affected if you are running Eclipse OpenJ9 versions 0.20.0 or earlier, or exactly version 0.21.0, on a Power platform (ppc64/ppc64le), and your application uses System.arraycopy with potentially oversized length parameters.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataUpgrade Eclipse OpenJ9 to version 0.21 or later on Power platforms to resolve the System.arraycopy flaw.
- Consultation1.0 h
- Implementation1.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,144.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-17639 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2019-17639 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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