# CVE-2026-42778: Apache MINA: CWE-502 Deserialization of Untrusted Data (take 2) > Attackers can execute arbitrary code via unsafe deserialization in Apache MINA if applications call IoBuffer.getObject(), requiring an upgrade to patched versions. - **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 1 May 2026 - **Updated:** 2 May 2026 - **Also known as:** CLEANSTART-2026-BH66717, CLEANSTART-2026-BN04389, CLEANSTART-2026-KZ81353, CLEANSTART-2026-VE14203, CLEANSTART-2026-YI69310, ECHO-a687-888d-d700, GHSA-995c-6rp3-4m4x, MINI-f97r-7fx7-v9x2, MINI-fwxj-hh8c-3prq, MINI-g782-frwr-hfcg, MINI-jc8h-ghv9-fpw8, MINI-pwq4-w722-h8q3, MINI-r4j3-4vcp-gwcq, MINI-x65m-f6vq-9j47, UBUNTU-CVE-2026-42778 ## What is CVE-2026-42778? CVE-2026-42778 is a critical unsafe deserialization vulnerability in Apache MINA, published on 1 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description 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 Weakness: CWE-502 (Deserialization of Untrusted Data) ## Which versions are affected by CVE-2026-42778? 4 open source packages ship an affected version, including org.apache.mina:mina-core. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `org.apache.mina:mina-core` | Maven | From 2.1.0 | 2.1.12 | | `org.apache.mina:mina-core` | Maven | From 2.1.0 | 2.1.12 | | `org.apache.mina:mina-core` | Maven | From 2.2.0 | 2.2.7 | | `org.apache.mina:mina-core` | Maven | From 2.2.0 | 2.2.7 | Products: Apache Mina. ## How do I fix CVE-2026-42778? Upgrade org.apache.mina:mina-core to a fixed version for your release line: 2.1.12 or 2.2.7. ## Is CVE-2026-42778 being exploited? There is no known exploitation of CVE-2026-42778 in the wild and no public exploit code. Public exploit code: - CVE-2026-42778 EUVD-2026-26492 Deserialization of Untrusted Data (CWE-502) (github_poc): https://github.com/Akinfue/CVE-2026-42778-POC ## Other vulnerabilities in Apache MINA - [CVE-2024-52046](https://insights.sbomify.com/CVE-2024-52046/): Apache MINA: MINA applications using unbounded deserialization may allow RCE (critical 10.0) - [CVE-2026-47065](https://insights.sbomify.com/CVE-2026-47065/): Apache MINA: Critical Deserialization Allow-list Bypass via resolveProxyClass - ZDRES-232 (critical 9.8) - [CVE-2026-42779](https://insights.sbomify.com/CVE-2026-42779/): Apache MINA vulnerable to Deserialization of Untrusted Data (CVE-2026-41635 Incomplete Fix) (critical 9.8) - [CVE-2026-41409](https://insights.sbomify.com/CVE-2026-41409/): Apache MINA: CWE-502 Deserialization of Untrusted Data (critical 9.8) - [CVE-2026-41635](https://insights.sbomify.com/CVE-2026-41635/): Apache MINA vulnerable to Deserialization of Untrusted Data (critical 9.8) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-42778 and fix it if it is affected. What it is: CVE-2026-42778 is a critical unsafe deserialization vulnerability in Apache MINA, published on 1 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-42778 in the wild and no public exploit code. Affected packages and fixed versions: - org.apache.mina:mina-core (Maven): affected from 2.1.0; fixed in 2.1.12 - org.apache.mina:mina-core (Maven): affected from 2.1.0; fixed in 2.1.12 - org.apache.mina:mina-core (Maven): affected from 2.2.0; fixed in 2.2.7 - org.apache.mina:mina-core (Maven): affected from 2.2.0; fixed in 2.2.7 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-42778/ (Markdown: https://insights.sbomify.com/CVE-2026-42778/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42778 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42778 - OSV: https://osv.dev/vulnerability/CVE-2026-42778 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-42778/ Summaries are generated and may contain mistakes; the official description above is the record.