In Eclipse OpenJ9 version 0.8.0, a vulnerability exists where, during execution of class files, if a superclass method that was previously concrete is recompiled as abstract, the runtime incorrectly delegates execution to an interface default method. This flaw corresponds to CWE-758 (Reliance on Undefined, Unspecified, or Implementation-Defined Behavior). The vulnerability has a CVSS 4.0 base score of 6.9, indicating medium severity. No vendor advisory or patch is currently provided, and no known exploits are reported in the wild.

The vulnerability may cause execution to follow unintended code paths by delegating to interface default methods when a superclass method is abstracted. This could potentially affect application behavior or security depending on the context of the affected methods. The CVSS vector indicates network attack vector with high attack complexity and partial user interaction required, suggesting exploitation is non-trivial. No direct evidence of active exploitation is known.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official fix or workaround is provided, users should monitor Eclipse Foundation communications for updates. Avoid using affected versions in sensitive environments until a fix is available.