Apache MINA’s AbstractIoBuffer.resolveClass() contains a flaw that allows the class allowlist to be bypassed for static classes or primitive types. The unchecked call to Class.forName() enables an attacker to deserialize arbitrary objects and execute code of their choosing. The weakness is classified as CWE-502. The impact is a full remote code execution with potential to compromise confidentiality, integrity, and availability of the affected application.

Customers using Apache Software Foundation’s Apache MINA within versions 2.0.0 to 2.0.27, 2.1.0 to 2.1.10, and 2.2.0 to 2.2.5 are impacted. Applications that employ IoBuffer.getObject() to deserialize data are also vulnerable. Any services that expose MINA over a network and process external traffic may expose this flaw.

The vulnerability has a CVSS score of 9.8, indicating critical severity. The EPSS score is less than 1% and it is not listed in CISA’s KEV catalog, suggesting limited exploitation in the wild. However, the likely attack vector is remote or network‑based, based on the use of IoBuffer.getObject() to process remote data. If an attacker can supply crafted serialized input, they can trigger the unchecked class resolution and achieve arbitrary code execution. The upgrade path to mitigated versions (2.0.28, 2.1.11, or 2.2.6+) is the only confirmed defensive measure currently available.