CVE-2026-42779: Apache MINA Deserialization Flaw Allows Remote Code Execution
A critical deserialization vulnerability, tracked as CVE-2026-42779, has been identified in Apache MINA. This flaw, rated 9.8 CVSS, stems from an incomplete fix for a prior issue (CVE-2026-41635). According to the National Vulnerability Database, the 2.1.X and 2.2.X branches of Apache MINA failed to properly apply the original patch, leaving a significant attack surface open.
The core issue lies within AbstractIoBuffer.resolveClass() where a specific branch, intended for static classes or primitive types, bypasses the classname allowlist entirely. This oversight permits arbitrary code execution by allowing attackers to inject malicious serialized objects. Any application utilizing Apache MINA that calls IoBuffer.getObject() is directly exposed to this critical vulnerability.
Defenders must prioritize patching. The National Vulnerability Database confirms that Apache MINA versions 2.1.0 through 2.1.11, and 2.2.0 through 2.2.6, are vulnerable. The fix, which applies the classname allowlist earlier in the process, is available in Apache MINA 2.1.12 and 2.2.7. Attackers will undoubtedly leverage this for initial access, given the prevalence of Apache MINA in network applications. This isn’t theoretical; deserialization flaws are a cornerstone of many sophisticated attacks.
What This Means For You
- If your organization uses Apache MINA, you need to identify all instances calling `IoBuffer.getObject()` immediately. This is a critical remote code execution vulnerability (CVE-2026-42779) and patching to Apache MINA 2.1.12 or 2.2.7 is non-negotiable. Assume compromise if you're running affected versions.
Related ATT&CK Techniques
🛡️ Detection Rules
4 rules · 6 SIEM formats4 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
Web Shell Activity Detection — CVE-2026-42779
title: Web Shell Activity Detection — CVE-2026-42779
id: scw-2026-05-01-1
status: experimental
level: high
description: |
Detects potential web shell interaction patterns following the CVE-2026-42779 breach.
author: SCW Feed Engine (auto-generated)
date: 2026-05-01
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-42779/
tags:
- attack.persistence
- attack.t1505.003
logsource:
category: webserver
detection:
selection:
cs-uri|endswith:
- '.php'
- '.jsp'
- '.aspx'
- '.ashx'
cs-uri-query|contains:
- 'cmd='
- 'exec='
- 'shell'
- 'upload'
condition: selection
falsepositives:
- Legitimate activity from CVE-2026-42779
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-42779 | RCE | Apache MINA 2.1.0 <= 2.1.11 |
| CVE-2026-42779 | RCE | Apache MINA 2.2.0 <= 2.2.6 |
| CVE-2026-42779 | RCE | Apache MINA AbstractIoBuffer.resolveClass() bypasses classname allowlist |
| CVE-2026-42779 | RCE | Applications using Apache MINA that call IoBuffer.getObject() |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 01, 2026 at 14:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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