What is CVE-2026-42778?

CVE-2026-42778 is a critical-severity vulnerability in Apache Mina, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-05-01.

How severe is CVE-2026-42778?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2026-42778 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Deserialization in Apache Mina

CVE-2026-42778

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 clas…

Vulnerability class: Insecure Deserialization

EPSS: 0.003 (52.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Apache Mina
Apache Software Foundation Mina — versions 2.2.X, 2.1.X

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

Public proof-of-concept exploits

Akinfue/CVE-2026-42778-POC

References

security@apache.org (vendor-advisory, Patch, Mailing List, Vendor Advisory)

Frequently asked questions

What is CVE-2026-42778?: CVE-2026-42778 is a critical-severity vulnerability in Apache Mina, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-05-01.
How severe is CVE-2026-42778?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2026-42778 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.