Raw vector
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:XSummary
CVE-2026-33701 is a critical-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Linuxfoundation Opentelemetry Instrumentation For Java. Its CVSS base score is 9.3 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 42% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-33701 affects OpenTelemetry Java Instrumentation libraries in versions prior to 2.26.1, which provide auto-instrumentation for Java applications. The vulnerability stems from the RMI instrumentation registering a custom endpoint that deserializes incoming data without applying serialization filters, enabling potential remote code execution (RCE) on JDK versions 16 and earlier. This issue is classified under CWE-502 (Deserialization of Untrusted Data) with a CVSS v3.1 base score of 9.8 (Critical), reflecting its high impact due to network-based exploitation without authentication.
Exploitation requires three conditions: OpenTelemetry Java Instrumentation attached as a Java agent (-javaagent) on JDK 16 or earlier; a JMX/RMI port explicitly configured via -Dcom.sun.management.jmxremote.port and network-reachable; and a gadget-chain-compatible library present on the classpath. An attacker with network access to the exposed JMX or RMI port can send malicious serialized data, achieving arbitrary RCE with the privileges of the user running the instrumented JVM.
Advisories recommend upgrading to version 2.26.1 or later for JDK versions below 17, while no immediate action is required for JDK 17 and above, though upgrading is encouraged. As a workaround, disable the RMI integration by setting the system property -Dotel.instrumentation.rmi.enabled=false. Details are available in the OpenTelemetry GitHub security advisory (GHSA-xw7x-h9fj-p2c7), the v2.26.1 release notes, and the fixing commit (9cf4fbaaa9e79226142b2ed42a6f6b4ac0be2197).
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-16498
Vulnerability Data
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can uncover deserialization flaws before deployment.
Input validation directly stops deserialization of untrusted data by ensuring inputs are valid before processing.
Engineering principles such as safe deserialization and input sanitization structurally prevent the weakness from being introduced.
Integrity verification tools can detect malformed or tampered serialized data after the fact.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
PR.PS-02 addresses only post-deployment updates/patching and cannot prevent introduction of unsafe deserialization code, yet it can remediate some instances when the flaw exists in outdated libraries or components.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing includes validation of deserialization routines and the use of untrusted data, reducing the likelihood that unsafe object reconstruction will be deployed.
Requiring vetted libraries, regular updates and SAST before release reduces the likelihood that deserialization logic will accept and act on attacker-controlled serialized objects.
Regular scanning of third-party libraries and timely patching reduce the likelihood that unsafe deserialization vulnerabilities remain active.
Mandatory malware scanning of data received over networks or storage media intercepts malicious serialized payloads before they are deserialized by the target application.