CVE-2026-33701
OpenTelemetry: Unsafe Deserialization in RMI Instrumentation may Lead to Remote Code Execution
Summary
In versions prior to 2.26.1, the RMI instrumentation registered a custom endpoint that deserialized incoming data without applying serialization filters. 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: 1. OpenTelemetry Java instrumentation is attached as a Java agent (`-javaagent`) 2. An RMI endpoint is network-reachable (e.g. JMX remote port, an RMI registry, or any application-exported RMI service) 3. A gadget-chain-compatible library is present on the classpath ### Impact Arbitrary remote code execution with the privileges of the user running the instrumented JVM. ### Recommendation Upgrade to version 2.26.1 or later. ### Workarounds Set the following system property to disable the RMI integration: ``` -Dotel.instrumentation.rmi.enabled=false ``` ### Credits This vulnerability was responsibly disclosed in coordination with Datadog.
Affected packages
| Ecosystem | Package | Affected versions | Fixed versions |
|---|---|---|---|
| Maven | io.opentelemetry.javaagent:opentelemetry-javaagent | — | 2.26.1 |
Remediation: Upgrade to 2.26.1 or later.
References
Includes data from the GitHub Advisory Database, licensed under CC-BY 4.0.
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EPSS scores provided by the FIRST.org Exploit Prediction Scoring System.