How severe is CVE-2026-16439?

CVE-2026-16439 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2026-16439 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-16439?

CVE-2026-16439 affects Eclipse Openj9. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-16439?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-16439 published?

CVE-2026-16439 was published on 2026-07-21 and last updated on 2026-08-11.

CVE-2026-16439

CVE-2026-16439 is a critical-severity vulnerability in Eclipse Openj9 with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-124.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v4: 5.8
EPSS exploit prediction: 0% (15th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-124
Affected product: Eclipse Openj9
Published: 2026-07-21
Last modified: 2026-08-11

Description

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

Frequently asked questions

What is CVE-2026-16439?: In Eclipse OpenJ9 versions up to 0.60, using -Xtrace to trace method arguments can lead to buffer underflow.
How severe is CVE-2026-16439?: CVE-2026-16439 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2026-16439 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-16439?: CVE-2026-16439 affects Eclipse Openj9. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-16439?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-16439 published?: CVE-2026-16439 was published on 2026-07-21 and last updated on 2026-08-11.

References

Affected products (1)

cpe:2.3:a:eclipse:openj9:*:*:*:*:*:*:*:*

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