# CVE-2026-42778: The fix for was not applied to the 2.1.X and 2.2.X branches. Here was the original issue description: The fix for CVE-202

Source: https://junglewise.ai/threats/cve-2026-42778-apache-mina-vulnerable-to-deserialization-of-untrusted-data  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-01  
License: CC BY 4.0 with a link back

CVE-2026-42778 · Severity: critical · CVSS 9.8 · Published 2026-05-01

The fix for CVE-2026-41409 was not applied to the 2.1.X and 2.2.X branches. Here was the original issue description:




The fix for CVE-2024-52046 in Apache MINA AbstractIoBuffer.getObject() was incomplete. The classname allowlist of classes allowed to be deserialized was applied too late after a static initializer in a class to be read might already have been executed.




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






The fix for CVE-2024-52046 in Apache MINA AbstractIoBuffer.getObject() was incomplete. The classname allowlist of classes allowed to be deserialized was applied too late after a static initializer in a class to be read might already have been executed.




Affected versions are Apache MINA 2.1.0 <= 2.1.110, 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

Technologies: [Apache Mina](https://junglewise.ai/threats/technologies/mina), [org.apache.mina:mina-core (Maven)](https://junglewise.ai/threats/technologies/org-apache-mina-mina-core). Vendors: [Apache](https://junglewise.ai/threats/vendors/apache), [Maven](https://junglewise.ai/threats/vendors/maven).

## Quick answers

**Is CVE-2026-42778 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42778 being exploited in the wild.

**How severe is CVE-2026-42778?** Critical severity, with a CVSS score of 9.8, published 1 May 2026.

**Which products and versions are affected?** org.apache.mina:mina-core (Maven) ECOSYSTEM:introduced=2.1.0,fixed=2.1.12.

**Is there a fix for CVE-2026-42778?** Yes. org.apache.mina:mina-core (Maven): upgrade to 2.1.12 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2026-42778?** Check whether you run Apache Mina or org.apache.mina:mina-core (Maven) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- org.apache.mina:mina-core (Maven): upgrade to 2.1.12 or later

  ```sh
  # set org.apache.mina:mina-core to 2.1.12 in your pom.xml or build.gradle
  ```


## Affected products

- Apache Mina
- org.apache.mina:mina-core (Maven) ECOSYSTEM:introduced=2.1.0,fixed=2.1.12

## Identifiers

- CVE-2026-42778
- GHSA-995c-6rp3-4m4x

## Related threats

- [Apache MINA JavaNativeMessageDecoder unsafe deserialization RCE](https://junglewise.ai/threats/cve-2026-118636-unsupported-when-assigned-javanativemessagedecoder-in-the-mina-3)
- [Apache MINA filter bypass via unpatched resolveProxyClass](https://junglewise.ai/threats/cve-2026-94301-the-fix-for-zdres-232-resolveproxyclass-not-overridden)
- [Apache MINA CompressionFilter decompression bomb DoS](https://junglewise.ai/threats/cve-2026-47321-the-compressionfilter-class-uses-zlib-to-deflate-and-inflate-data)
- [Apache Java Deserialization filter bypass via resolveProxyClass](https://junglewise.ai/threats/cve-2026-47065-apache-java-deserialization-filter-bypass-via-resolveproxyclass)
- [The fix for was not applied to the 2.1.X and 2.2.X branches. Here was the original issue description: Apache MINA'](https://junglewise.ai/threats/cve-2026-42779-apache-mina-vulnerable-to-deserialization-of-untrusted-data)