The fix for CVE-2026-41635 was not applied to the 2.1.X and 2.2.X branches. Here was the original issue description:
Apache MINAs AbstractIoBuffer.resolveClass() contains two branches, one of them (for static classes or primitive types) does not check the class at all, bypassing the classname allowlist and allowing arbitrary code to be executed.
The fix checks if the class is present in the accepted class filter before calling Class.forName().
Affected versions are Apache MINA 2.1.0 <= 2.1.11, and 2.2.0 <= 2.2.6.
The problem is resolved in Apache MINA 2.1.12, and 2.2.7 by applying the classname allowlist earlier.
Affected are applications using Apache MINA that call IoBuffer.getObject().
Applications using Apache MINA are advised to upgrade.
Weakness
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Mina | Apache | 2.1.0 (including) | 2.1.12 (excluding) |
| Mina | Apache | 2.2.0 (including) | 2.2.7 (excluding) |
| Mina2 | Ubuntu | devel | * |
| Mina2 | Ubuntu | esm-apps/jammy | * |
| Mina2 | Ubuntu | esm-apps/noble | * |
| Mina2 | Ubuntu | esm-apps/resolute | * |
| Mina2 | Ubuntu | jammy | * |
| Mina2 | Ubuntu | noble | * |
| Mina2 | Ubuntu | questing | * |
| Mina2 | Ubuntu | resolute | * |
Potential Mitigations
- Make fields transient to protect them from deserialization.
- An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.