CVE-2026-33701

CRITICAL

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

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2026-33701. PoCs published by pl4tyz.

AI-analyzed exploit summary This repository provides a detailed technical analysis of CVE-2026-33701, an unsafe deserialization vulnerability in OpenTelemetry Java Agent RMI Instrumentation. It includes root cause analysis, patch details, and exploit conditions.

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.

Exploits (1)

nomisec WRITEUP
by pl4tyz · poc
https://github.com/pl4tyz/CVE-2026-33701-Unsafe-Deserialization-in-OpenTelemetry-Java-Agent-RMI-Instrumentation

This repository provides a detailed technical analysis of CVE-2026-33701, an unsafe deserialization vulnerability in OpenTelemetry Java Agent RMI Instrumentation. It includes root cause analysis, patch details, and exploit conditions.

Classification
Writeup 100%
Attack Type
Deserialization
Complexity
Moderate
Reliability
Reliable
Target: OpenTelemetry Java Agent < 2.26.1
No auth needed
Prerequisites: OpenTelemetry Java Agent attached on JDK 16 or lower · Network-reachable RMI or JMX port · Gadget-chain-compatible library on classpath
devstral-2 · analyzed Apr 08, 2026 Full analysis →

Scores

CVSS v3 9.8
EPSS 0.0021
EPSS Percentile 44.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact total

Details

CWE
CWE-502
Status published
Products (3)
io.opentelemetry.javaagent/opentelemetry-javaagent 0 - 2.26.1Maven
linuxfoundation/opentelemetry_instrumentation_for_java < 2.26.1
open-telemetry/opentelemetry-java-instrumentation < 2.26.1
Published Mar 27, 2026
Tracked Since Mar 27, 2026