---
title: "CVE-2026-33701: OpenTelemetry: Unsafe Deserialization in RMI Instrumentation may Lead to Remote Code Execution"
url: https://erroneo.us/security/cve/CVE-2026-33701/
description: "CVE-2026-33701 (io.opentelemetry.javaagent:opentelemetry-javaagent (Maven)): OpenTelemetry Java Instrumentation provides OpenTelemetry auto-instrumentation…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-03-27
date_modified: 2026-08-17
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-33701"
kev: false
cvss: 9.3
epss: 0.01108
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-33701: OpenTelemetry: Unsafe Deserialization in RMI Instrumentation may Lead to Remote Code Execution

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 1.1% , percentile 66: FIRST’s model estimates a 1.1% chance of exploitation activity in the next 30 days, higher than 66% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes io.opentelemetry.javaagent:opentelemetry-javaagent (Maven) < 2.26.1, fixed in 2.26.1 . Check your lockfile, including transitive dependencies.

## What it is

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

## Affected packages

- Maven `io.opentelemetry.javaagent:opentelemetry-javaagent` < 2.26.1 → fixed: 2.26.1

## Affected products (CVE record)

- open-telemetry opentelemetry-java-instrumentation: < 2.26.1

## Severity

- GitHub_M CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`
- redhat-SADP CVSS 3.1: 8.1 `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 4.0: 9.3 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 1.11% probability of exploitation activity in the next 30 days; percentile 66.

## Sources

- [GitHub Advisory GHSA-xw7x-h9fj-p2c7](https://github.com/advisories/GHSA-xw7x-h9fj-p2c7)
- [CVE.org record CVE-2026-33701](https://www.cve.org/CVERecord?id=CVE-2026-33701)
- [NVD entry CVE-2026-33701](https://nvd.nist.gov/vuln/detail/CVE-2026-33701)
- [github.com](https://github.com/open-telemetry/opentelemetry-java-instrumentation/security/advisories/GHSA-xw7x-h9fj-p2c7)
- [github.com](https://github.com/open-telemetry/opentelemetry-java-instrumentation/commit/9cf4fbaaa9e79226142b2ed42a6f6b4ac0be2197)
- [github.com](https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases/tag/v2.26.1)
- [access.redhat.com](https://access.redhat.com/security/cve/CVE-2026-33701)
- [RHBZ#2452071](https://bugzilla.redhat.com/show_bug.cgi?id=2452071)
- [security.access.redhat.com](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33701.json)

---
Source page: https://erroneo.us/security/cve/CVE-2026-33701/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt