Summary
OpenDJ Pre-Auth RCE via Java Deserialization in JMX RMI
Description
A Deserialization of Untrusted Data (CWE-502) issue in OpenDJ's JMX RMI connector allows an unauthenticated remote attacker to deserialize arbitrary Java objects on the server. The vulnerability exists because the platform reads and processes attacker-controlled bytes prior to authentication. This affects OpenDJ Community Edition through 5.1.0. This has been patched in version 5.1.1.
Impact
This impacts all current OpenDJ releases where the JMX Connection Handler is enabled. While disabled by default, it is frequently enabled in practice for monitoring integrations. Exploitation requires TCP reachability to the configured listener and does not require authentication, prior privileges, or client certificates. Successful exploitation results in unauthenticated Remote Code Execution (RCE), with the severity depending on the runtime classpath and Java version. Unauthenticated RCE was demonstrated on the OpenDJ 4.4.15 (JDK 11 + Jackson 2.12.6.1).
Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect. Typical impact: arbitrary code execution or logic abuse.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
This has been patched in OpenDJ Community Edition version 5.1.1. Users are encouraged to update to the latest release.
Frequently Asked Questions
- What is CVE-2026-46495? CVE-2026-46495 is a critical-severity insecure deserialization vulnerability in org.openidentityplatform.opendj:opendj-server-legacy (maven), affecting versions <= 5.1.0. It is fixed in 5.1.1. Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect.
- Which versions of org.openidentityplatform.opendj:opendj-server-legacy are affected by CVE-2026-46495? org.openidentityplatform.opendj:opendj-server-legacy (maven) versions <= 5.1.0 is affected.
- Is there a fix for CVE-2026-46495? Yes. CVE-2026-46495 is fixed in 5.1.1. Upgrade to this version or later.
- Is CVE-2026-46495 exploitable, and should I be worried? Whether CVE-2026-46495 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-46495 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-46495? Upgrade
org.openidentityplatform.opendj:opendj-server-legacyto 5.1.1 or later.