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CVE-2026-33701

Severity9.3 Critical CVSS 4.0 3 scores
Fixed in2.26.1
WeaknessDeserialization of untrusted data (CWE-502)
Published27 Mar 2026
Updated4 Aug 2026

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.

Exploitation status

No public exploit

No exploit has been reported in the sources we check. The 1 repository below are public GitHub repositories with fewer than 5 stars.

  • CISA KEV not listed
  • VulnCheck KEV not listed
  • CISA Vulnrichment exploitation: none
  • Indexed PoC 1 indexed, none at 5+ stars
  • EPSS 0.96% chance in 30 days

1 of these are GitHub repositories with fewer than 5 stars. They are listed for reference and don't count toward the exploitation status above.

IndexArtifactStarsFirst seen
GitHub PoC CVE-2026-33701 Unsafe Deserialization in OpenTelemetry Java Agent RMI Instrumentation 2026-04-04

Waratek protection

Protected by Waratek

Waratek has a rule that blocks attacks on this vulnerability.

Decided by A vulnerability class already blocked by an ARMR security rule
Finding Protected by Waratek's ARMR deserialization security rule, which blocks this class of attack at the JVM level without a rule written for this CVE specifically. The CVE's weakness is CWE-502: Deserialization of Untrusted Data.
Candidate fix https://github.com/open-telemetry/opentelemetry-java-instrumentation/commit/9cf4fbaaa9e79226142b2ed42a6f6b4ac0be2197 : a commit: the change itself

How to mitigate CVE-2026-33701

Upgrade the affected software to 2.26.1 or later. Until you can, Waratek RASP blocks exploitation with its deserialization and process rules. It runs inside the Java application, with no code changes.

Waratek RASP Runtime protection for Java applications

CVSS

9.3 CRITICAL v4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X 3 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

VersionScoreBandVectorAssignerType
CVSS 4.0 9.3 CRITICAL 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X security-advisories@github.com Secondary published
CVSS 3.1 9.8 CRITICAL CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H NVD Primary
CVSS 3.1 8.1 HIGH CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H redhat-SADP Secondary

Affected software and releases

Oracle advisories

AdvisoryTypeQuarterProducts Oracle names in its risk matrix
Oracle Critical Patch Update October 2026 ↗ CPU 2026-Q4 Oracle Communications / Configuration (glibc) (25.2.201)

Oracle components and versions

FamilyComponentVersions, as Oracle lists themRead as
Oracle Communications Configuration (glibc) 25.2.201 25.2.201

Maven packages

Affected and fixed versions, from OSV.dev
PackageIntroducedFixedLast affected
io.opentelemetry.javaagent:opentelemetry-javaagent 0 2.26.1 unbounded

Products and versions

2 products, 2 version entries
SourceVendorProductSchemeAffected versions
osv io.opentelemetry.javaagent opentelemetry-javaagent generic < 2.26.1
nvd linuxfoundation opentelemetry instrumentation for java generic < 2.26.1

References

URLTags
https://github.com/open-telemetry/opentelemetry-java-instrumentation/commit/9cf4fbaaa9e79226142b2ed42a6f6b4ac0be2197 commit
https://github.com/open-telemetry/opentelemetry-java-instrumentation/security/advisories/GHSA-xw7x-h9fj-p2c7 WEB
https://access.redhat.com/security/cve/CVE-2026-33701 WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2452071 WEB
https://github.com/open-telemetry/opentelemetry-java-instrumentation PACKAGE
https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases/tag/v2.26.1 WEB
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33701.json WEB

Timeline

Published2026-03-27By the CVE Program.
NVD record modified2026-08-04NVD's own last-modified date for this record.