CVE-2026-16439: In Eclipse OpenJ9 versions up to 0.60, using -Xtrace to trace method arguments can lead to buffer underflow.

This month

CRITICAL 9.1REMOTEUPGRADE

CVE-2026-16439 is a critical-severity flaw (CVSS 9.1) affecting openj9. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 64%)
CISA exploited list	No
Weakness	CWE-124
Published	2026-07-21
Last modified	2026-10-24

Publisher (CNA): Eclipse Foundation · Vendor: eclipse

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-21 18:16 UTCPublished CVE record published
2026-10-24 19:10 UTCUpdated Record last modified

eclipse openj9 UPGRADE

Affected: >= 0.8.0 and < 0.60.0

Fixed in: 0.60.0

Safe to downgrade to: a release before 0.8.0

1. Check installed version

apt-cache policy openj9 || rpm -q openj9 || openj9 --version

2. UPGRADE to 0.60.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade openj9

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade openj9

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 0.8.0 (Debian / Ubuntu)

apt-cache madison openj9 sudo apt install openj9=<VERSION_BEFORE_0.8.0> sudo apt-mark hold openj9

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

dnf --showduplicates list openj9 sudo dnf downgrade openj9-<VERSION_BEFORE_0.8.0> sudo dnf versionlock add openj9

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.

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-2026-16439?

openj9: upgrade to 0.60.0. Exact commands for each OS are on this page.

Is CVE-2026-16439 being exploited?

CVE-2026-16439 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-2026-16439 affect?

CVE-2026-16439 affects openj9. Severity is critical (CVSS 9.1). In Eclipse OpenJ9 versions up to 0.60, using -Xtrace to trace method arguments can lead to buffer underflow.

How urgent is CVE-2026-16439?

Priority 46/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-16441 CRITICAL 9.6 UPGRADE In Eclipse OpenJ9 versions up to 0.60, when executing class files where a previously concrete superclass metho

References

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