---
title: "CVE-2026-42778: Apache MINA vulnerable to Deserialization of Untrusted Data (CVE-2026-41409 Incomplete Fix)"
url: https://erroneo.us/security/cve/CVE-2026-42778/
description: "CVE-2026-42778 (org.apache.mina:mina-core (Maven)): The fix for CVE-2026-41409 was not applied to the 2.1.X and 2.2.X branches. Here was the original issue…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-05-01
date_modified: 2026-05-07
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-42778"
kev: false
cvss: 9.8
epss: 0.00752
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-42778: Apache MINA vulnerable to Deserialization of Untrusted Data (CVE-2026-41409 Incomplete Fix)

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.8% , percentile 54: FIRST’s model estimates a 0.8% chance of exploitation activity in the next 30 days, higher than 54% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes org.apache.mina:mina-core (Maven) >= 2.1.0, < 2.1.12, fixed in 2.1.12 ; org.apache.mina:mina-core (Maven) >= 2.2.0, < 2.2.7, fixed in 2.2.7 . Check your lockfile, including transitive dependencies.

## What it is

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

## Affected packages

- Maven `org.apache.mina:mina-core` >= 2.1.0, < 2.1.12 → fixed: 2.1.12
- Maven `org.apache.mina:mina-core` >= 2.2.0, < 2.2.7 → fixed: 2.2.7

## Affected products (CVE record)

- Apache Software Foundation Apache MINA: 2.2.X <= 2.2.6, 2.1.X <= 2.1.11

## Severity

- apache CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.75% probability of exploitation activity in the next 30 days; percentile 54.

## Sources

- [lists.apache.org](https://lists.apache.org/thread/fhlx5k91hrkgyzh7yk1nghrn3k27gxy0)
- [GitHub Advisory GHSA-995c-6rp3-4m4x](https://github.com/advisories/GHSA-995c-6rp3-4m4x)
- [CVE.org record CVE-2026-42778](https://www.cve.org/CVERecord?id=CVE-2026-42778)
- [NVD entry CVE-2026-42778](https://nvd.nist.gov/vuln/detail/CVE-2026-42778)
- [github.com](https://github.com/advisories/GHSA-76h9-2vwh-w278)
- [github.com](https://github.com/advisories/GHSA-f2wh-grmh-r6jm)

---
Source page: https://erroneo.us/security/cve/CVE-2026-42778/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt