Vulnerability · Published Mar 27, 2026 · Assigned by GitHub_M
CVE-2026-33701OpenTelemetry: Unsafe Deserialization in RMI Instrumentation may Lead to Remote Code Execution
High 8.1
In plain English
A high-severity unsafe deserialization in opentelemetry-java-instrumentation from open-telemetry. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 61% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Maven | io.opentelemetry.javaagent:opentelemetry-javaagent | 2.26.1 | GHSA-xw7x-h9fj-p2c7 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| open-telemetry | opentelemetry-java-instrumentation | < 2.26.1 |
Weakness: CWE-502 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://github.com/open-telemetry/opentelemetry-java-instrumentation/security/advisories/GHSA-xw7x-h9fj-p2c7 x_refsource_CONFIRM
- https://github.com/open-telemetry/opentelemetry-java-instrumentation/commit/9cf4fbaaa9e79226142b2ed42a6f6b4ac0be2197 x_refsource_MISC
- https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases/tag/v2.26.1 x_refsource_MISC
- https://access.redhat.com/security/cve/CVE-2026-33701 vdb-entry, x_refsource_REDHAT
- RHBZ#2452071 issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33701.json x_sadp-csaf-vex