OpenTelemetry: Unsafe Deserialization in RMI Instrumentation may Lead to Remote Code Execution

Summary

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.

Timeline

1. Mar 27, 2026, 12:01 AM UTCCVE published
2. Mar 27, 2026, 1:26 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: yes · Technical impact: total

3. Aug 17, 2026, 12:04 PM UTCRecord last updated

Affected versions

• open-telemetry opentelemetry-java-instrumentation

  fixed in 2.26.1

• io.opentelemetry.javaagent:opentelemetry-javaagentMaven

  fixed in 2.26.1

References 4