CVE-2026-33701: linuxfoundation opentelemetry_instrumentation_for_java Deserialization of Untrusted Data

Vulnerability summary

CVE-2026-33701 is a critical (CVSS 9.8) Deserialization of Untrusted Data vulnerability in linuxfoundation opentelemetry_instrumentation_for_java. EPSS estimates a 1.11% chance of exploitation in the next 30 days, higher than 65.3% of scored vulnerabilities.

Timeline

1. 27-03-2026
   PublishedVulnerability first disclosed.
2. 17-08-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-502Deserialization of Untrusted DataThe product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.