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Opentelemetry Instrumentation For JavaApplication · Linuxfoundation

CVE-2026-33701

CRITICAL · 9.8 CVSS v3.1 Published 2026-03-27
Fix available
A fix is available. Upgrade to 2.26.1 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

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
OpenTelemetry Java Instrumentation provides OpenTelemetry auto-instrumentation and instrumentation libraries for Java. In versions prior to 2.26.1, the RMI instrumentation registered a custom endpoint that deserialized incoming data without applying serialization filters. On JDK version 16 and earlier, an attacker with network access to a JMX or RMI port on an instrumented JVM could exploit this to potentially achieve remote code execution. All three of the following conditions must be true to exploit this vulnerability: First, OpenTelemetry Java instrumentation is attached as a Java agent (`-javaagent`) on Java 16 or earlier. Second, JMX/RMI port has been explicitly configured via `-Dcom.sun.management.jmxremote.port` and is network-reachable. Third, gadget-chain-compatible library is present on the classpath. This results in arbitrary remote code execution with the privileges of the user running the instrumented JVM. For JDK >= 17, no action is required, but upgrading is strongly encouraged. For JDK < 17, upgrade to version 2.26.1 or later. As a workaround, set the system property `-Dotel.instrumentation.rmi.enabled=false` to disable the RMI integration.

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

The RMI instrumentation in OpenTelemetry Java versions prior to 2.26.1 registers a custom endpoint that deserializes incoming data without applying serialization filters. On Java 16 or earlier, an attacker with network access to a configured JMX/RMI port can exploit this to achieve remote code execution if a gadget-chain-compatible library exists on the classpath.

MitigationUpgrade OpenTelemetry Java Instrumentation to version 2.26.1 or later; alternatively, disable the RMI instrumentation by setting `-Dotel.instrumentation.rmi.enabled=false` as a JVM argument.

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
Opentelemetry Instrumentation For JavaApplication
Affected:< 2.26.1

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
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/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 OpenTelemetry Java Instrumentation version
    Check the version of the opentelemetry-java-instrumentation agent or JAR file in your environment (check build files, lib folder, or runtime classpath for the instrumentation library version)
    Affected if The installed version is below 2.26.1 (e.g., 2.26.0, 2.25.0, etc.)
  2. Determine if RMI instrumentation is enabled
    Check for the system property -Dotel.instrumentation.rmi.enabled or look for this property in your application startup scripts, environment variables, or configuration files
    Affected if The property is set to true or is not explicitly set to false (default behavior enables RMI instrumentation)
  3. Identify the Java runtime version
    Run 'java -version' or check the JAVA_HOME environment to determine the JDK/JRE version
    Affected if The runtime is Java 16 or earlier (JDK 8, 9, 10, 11, 12, 13, 14, 15, or 16)
  4. Check if JMX/RMI ports are exposed
    Review your application configuration, firewall rules, or network settings for any exposed JMX/RMI listener ports (typically port 1099 or custom RMI ports)
    Affected if The application has an accessible JMX/RMI port reachable from the network

You are affected if you have OpenTelemetry Java Instrumentation version below 2.26.1, RMI instrumentation is enabled (default), Java 16 or earlier is in use, and a JMX/RMI port is network-accessible.

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
Upgrade available Upgrade to 2.26.1 or later
Fixed in 2.26.1
Vendor patch github.com →
Interim mitigation

Upgrade OpenTelemetry Java Instrumentation to version 2.26.1 or later; alternatively, disable the RMI instrumentation by setting `-Dotel.instrumentation.rmi.enabled=false` as a JVM argument.

Recommended fix High confidence

2.26.1

  1. Upgrade to OpenTelemetry Java Instrumentation version 2.26.1 or later by updating your build configuration (Maven, Gradle, or the -javaagent JAR reference)
  2. Verify the upgrade by checking that the instrumentation version matches or exceeds 2.26.1
  3. If immediate upgrade is not possible and JDK < 17 is in use, add the JVM argument `-Dotel.instrumentation.rmi.enabled=false` to disable the vulnerable RMI integration
  4. Ensure JMX/RMI ports are not network-exposed if possible, as this is a required condition for exploitation

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

Fix this in Opentelemetry Instrumentation For Java Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

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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-2026-33701 in production — separate from our analysis above.

No notes yet

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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