Deserialization in Linuxfoundation Opentelemetry Instrumentation For Java
CVE-2026-33701
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.
Vulnerability class: Insecure Deserialization
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.011 (64.5th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 65th percentile — 64.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.011 · change: +0.002
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- https://github.com/open-telemetry/opentelemetry-java-instrumentation/security/advisories/GHSA-xw7x-h9fj-p2c7 (Mitigation, Vendor Advisory)
- https://github.com/open-telemetry/opentelemetry-java-instrumentation/commit/9cf4fbaaa9e79226142b2ed42a6f6b4ac0be2197 (Patch)
- https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases/tag/v2.26.1 (Release Notes)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-33701?
- CVE-2026-33701 is a critical-severity vulnerability in Linuxfoundation Opentelemetry Instrumentation For Java, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-03-27.
- How severe is CVE-2026-33701?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2026-33701 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.