CVE-2026-41635: Apache MINA: AbstractIoBuffer.resolveClass() null-clazz Branch Skips acceptMatchers Filter — Full Object Deserialization RCE
Apache MINA's 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 2.0.0 <= 2.0.27, 2.1.0 <= 2.1.10, and
2.2.0 <= 2.2.5.
The problem is resolved in Apache MINA 2.0.28, 2.1.11, and 2.2.6 by applying the classname allowlist earlier.
Affected are applications using Apache MINA that call IoBuffer.getObject().
Applications using Apache MINA are advised to upgrade.
Other sources
Apache MINA's 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 2.0.0 = 2.0.27, 2.1.0 = 2.1.10, and
2.2.0 = 2.2.5.
The problem is resolved in Apache MINA 2.0.28, 2.1.11, and 2.2.6 by applying the classname allowlist earlier.
Affected are applications using Apache MINA that call IoBuffer.getObject().
Applications using Apache MINA are advised to upgrade.
— IBM
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Apache MINAto a version that resolves this vulnerability.Fixed in 2.0.28 - Upgrade
Upgrade
Apache MINAto a version that resolves this vulnerability.Fixed in 2.1.11 - Upgrade
Upgrade
Apache MINAto a version that resolves this vulnerability.Fixed in 2.2.6 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Patch ZDS-059
Event History
Frequently Asked Questions
What is the severity of CVE-2026-41635?
CVE-2026-41635 has been classified as a critical severity vulnerability due to its potential to allow remote code execution.
How do I fix CVE-2026-41635?
To fix CVE-2026-41635, upgrade Apache MINA to version 2.0.28, 2.1.11, or 2.2.6 or later.
What versions of Apache MINA are affected by CVE-2026-41635?
CVE-2026-41635 affects Apache MINA versions from 2.0.0 to 2.0.27, 2.1.0 to 2.1.10, and 2.2.0 to 2.2.5.
What impacts does CVE-2026-41635 have on affected systems?
CVE-2026-41635 can lead to full object deserialization remote code execution, allowing attackers to execute arbitrary code on affected systems.
Are there any workarounds for CVE-2026-41635?
There are no effective workarounds for CVE-2026-41635; the only solution is to upgrade to a patched version of Apache MINA.