CVE-2026-42778: The fix for CVE-2026-41409 was not applied to the 2.1.X and 2.2.X branches

Q: How do I fix CVE-2026-42778?

mina: upgrade to 2.1.12, 2.2.7. Exact commands for each OS are on this page.

Q: Is CVE-2026-42778 being exploited?

CVE-2026-42778 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-42778 affect?

CVE-2026-42778 affects mina. Severity is critical (CVSS 9.8). 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 class

Q: How urgent is CVE-2026-42778?

Priority 60/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.8REMOTEWATCHLISTUPGRADE

CVE-2026-42778 is a critical-severity flaw (CVSS 9.8) affecting mina. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 49%)
CISA exploited list	No
Weakness	CWE-502
Published	2026-05-01
Last modified	2026-10-26

Publisher (CNA): Apache Software Foundation · Vendor: apache

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-01 11:16 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

apache mina UPGRADE

Affected: >= 2.1.0 and < 2.1.12 · >= 2.2.0 and < 2.2.7

Fixed in: 2.1.12, 2.2.7

Safe to downgrade to: a release before 2.1.0

1. Check installed version

apt-cache policy mina || rpm -q mina || mina --version

2. UPGRADE to 2.1.12 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mina

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mina

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.1.0 (Debian / Ubuntu)

apt-cache madison mina sudo apt install mina=<VERSION_BEFORE_2.1.0> sudo apt-mark hold mina

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list mina sudo dnf downgrade mina-<VERSION_BEFORE_2.1.0> sudo dnf versionlock add mina

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

Maven · org.apache.mina:mina-core · FIXED · 2.1.12 · vulnerable: >= 2.1.0, < 2.1.12 · source

Set org.apache.mina:mina-core to 2.1.12 or later in pom.xml or build.gradle, then rebuild and redeploy.

Fedora ELN · openbao · FIXED · 2.6.5-1.eln159 · FEDORA-2026-77adf886ae · source

sudo dnf upgrade --advisory=FEDORA-2026-77adf886ae

Fedora 46 · sugar-turtleart · FIXED · 220-16.fc46 · FEDORA-2026-b79483c788 · source

sudo dnf upgrade --advisory=FEDORA-2026-b79483c788

RHEL 8 · javapackages-tools:201801/maven-wagon · NOT AFFECTED

RHEL 9 · maven:3.9/maven-wagon · NOT AFFECTED

RHEL 9 · maven-wagon · NOT AFFECTED

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: Akinfue/CVE-2026-42778-POC (0 stars)

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-42778?

mina: upgrade to 2.1.12, 2.2.7. Exact commands for each OS are on this page.

Is CVE-2026-42778 being exploited?

CVE-2026-42778 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-42778 affect?

CVE-2026-42778 affects mina. Severity is critical (CVSS 9.8). 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 class

How urgent is CVE-2026-42778?

Priority 60/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Related CVEs

CVE-2026-42779 CRITICAL 9.8 UPGRADE The fix for CVE-2026-41635 was not applied to the 2.1.X and 2.2.X branches
CVE-2026-41635 CRITICAL 9.8 UPGRADE Apache MINA's AbstractIoBuffer.resolveClass() contains two branches, one of them (for static classes or primit
CVE-2026-41409 CRITICAL 9.8 UPGRADE The fix for CVE-2024-52046 in Apache MINA AbstractIoBuffer.getObject() was incomplete

References

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