How do I check whether I am affected by CVE-2026-83387?

- Run `java -version` and compare against the affected versions listed in the sources (8u503, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27). - Run `native-image --version` or check GraalVM builds if GraalVM for JDK or GraalVM Enterprise is in use. - Check whether any service exposes JDBC-backed APIs that accept untrusted input.

What is the fix for CVE-2026-83387?

- Upgrade Oracle Java SE to a patched release for your major line, as listed in the Oracle Critical Patch Update for this CVE (exact fixed versions: unknown from these sources). - Upgrade Oracle GraalVM for JDK 17 or 21 and GraalVM Enterprise Edition to the patched builds (exact versions: unknown from these sources).

Who is not affected by CVE-2026-83387?

Not affected if: default-config.

Live › vulnerability › CVE-2026-83387

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medium5.9Runtime

Oracle Java SE JDBC flaw lets unauthenticated network attacker read data

A flaw in the JDBC component of Oracle Java SE and GraalVM lets an unauthenticated attacker over the network reach data the application can access. The attack is hard to carry out and the main impact is loss of confidentiality.

Summary written from the sources below. Check the originals before acting.

CVSS 3.x

5.9

medium

scored by [email protected]

known so far3 of 6

missing: versions, primary source, exploitation

First public: Oct 20, 2026 UTC
Last modified: Oct 21, 2026
Status: open
Known exploitation: None reported
Public exploit: None on GitHub
EPSS: not scored

First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.

Why it is medium, and not just CVSS

Likelihood → · Impact ↓

critical

high

medium

high

medium

low

medium

low

Exploited: No reports yet.
Needs login: No.
Needs a special setup: Not known from the sources.
Reachable from: internet.
Worst case: Attacker reads critical data accessible to the Java application.
CVSS said: 5.9. The facts above say high; we keep the sources' medium until an analyst looks.

Who is affected

Teams running Oracle Java SE or Oracle GraalVM builds on the listed versions, especially servers that expose JDBC-backed web services to untrusted input. Client deployments that run untrusted sandboxed applets or Java Web Start apps are also named in the advisory. Systems on patched runtimes can skip this.

Know the next one before it finds you.

Add to Slack

Live › vulnerability › CVE-2026-83387

Go to dashboard

medium5.9Runtime

Oracle Java SE JDBC flaw lets unauthenticated network attacker read data

Summary written from the sources below. Check the originals before acting.

CVSS 3.x

5.9

medium

scored by [email protected]

known so far3 of 6

missing: versions, primary source, exploitation

First public: Oct 20, 2026 UTC
Last modified: Oct 21, 2026
Status: open
Known exploitation: None reported
Public exploit: None on GitHub
EPSS: not scored

First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.

Why it is medium, and not just CVSS

Likelihood → · Impact ↓

critical

high

medium

high

medium

low

medium

low

Exploited: No reports yet.
Needs login: No.
Needs a special setup: Not known from the sources.
Reachable from: internet.
Worst case: Attacker reads critical data accessible to the Java application.
CVSS said: 5.9. The facts above say high; we keep the sources' medium until an analyst looks.

Who is affected

Know the next one before it finds you.

Add to Slack

Oracle Java SE JDBC flaw lets unauthenticated network attacker read data

Why it is medium, and not just CVSS

Who is affected

Know the next one before it finds you.

Oracle Java SE JDBC flaw lets unauthenticated network attacker read data

Why it is medium, and not just CVSS

Who is affected

Know the next one before it finds you.

How to check

The fix

Who had it, and when

What the sources say, verbatim

Sources