What is CVE-2026-16439?

CVE-2026-16439 is a critical-severity vulnerability in Eclipse Openj9, classified under Buffer Underwrite. CVSS score: 9.1/10. Published 2026-07-21.

How severe is CVE-2026-16439?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Vulnerability in Eclipse Openj9

CVE-2026-16439

In Eclipse OpenJ9 versions up to 0.60, using -Xtrace to trace method arguments can lead to buffer underflow.

Published 2026-07-21 · last modified 2026-08-11.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (36.2th percentile), scored 2026-10-22.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 36.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002

Affected products

Eclipse Openj9
Eclipse Foundation Openj9 — versions 0.8.0, 0, 0.60.0

Weakness classification (CWE)

CWE-124 — Buffer Underwrite

References

github.com/eclipse-openj9/openj9/pull/24394 (Patch, Issue Tracking)
gitlab.eclipse.org/security/cve-assignment/-/work_items/192 (Broken Link)

Frequently asked questions

What is CVE-2026-16439?: CVE-2026-16439 is a critical-severity vulnerability in Eclipse Openj9, classified under Buffer Underwrite. CVSS score: 9.1/10. Published 2026-07-21.
How severe is CVE-2026-16439?: Critical severity. CVSS v3 base score is 9.1 out of 10.