OpenDJ is an LDAPv3 compliant directory service. Prior to 5.1.1, the JMX RMI connector in opendj-server-legacy/src/main/java/org/opends/server/protocols/jmx/RmiConnector.java processes attacker-controlled credential objects before authentication without a restrictive jmx.remote.rmi.server.credentials.filter.pattern, and RmiAuthenticator.authenticate in opendj-server-legacy/src/main/java/org/opends/server/protocols/jmx/RmiAuthenticator.java accepts an unconstrained Object array rather than a two-element String[]. When the JMX Connection Handler is enabled and its TCP listener is reachable, an unauthenticated remote attacker can submit a crafted serialized Java object and achieve code execution in the OpenDJ server process. The handler is disabled by default, and successful exploitation depends on the runtime classpath and Java version; remote code execution was demonstrated against OpenDJ 4.4.15 on JDK 11 with Jackson 2.12.6.1. This issue is fixed in 5.1.1.
https://github.com/OpenIdentityPlatform/OpenDJ/security/advisories/GHSA-43x2-g84q-fmqx
https://github.com/OpenIdentityPlatform/OpenDJ/releases/tag/5.1.1
https://github.com/OpenIdentityPlatform/OpenDJ/pull/651
https://github.com/OpenIdentityPlatform/OpenDJ/commit/d4a95c2e37c375756f9829c7ec43a4785b99e2e2
https://github.com/OpenIdentityPlatform/OpenDJ/commit/7e3a75903159153c877daeb2952a552701e38044
Published: 2026-09-15
Updated: 2026-09-25
Base Score: 7.5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P
Severity: High
Base Score: 9.8
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: Critical
Base Score: 9.2
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Severity: Critical
EPSS: 0.00731