CVE-2026-16439Network attack vector

Memory corruption via pre-buffer null write

Published Jul 21, 2026 · Updated Jul 21, 2026

Buffer underflow in Eclipse OpenJ9 allows remote authenticated users to corrupt JVM memory through method-argument tracing. The traceMethodArguments implementation writes a null immediately before its allocated argument buffer when tracing a method with no arguments. Exploitation requires method-argument tracing, low privileges, user interaction, and specific runtime conditions; integrity and availability can be affected.

CVSS severity5.8
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer underflow in Eclipse OpenJ9 allows remote authenticated users to corrupt JVM memory through method-argument tracing. The traceMethodArguments implementation writes a null immediately before its allocated argument buffer when tracing a method with no arguments. Exploitation requires method-argument tracing, low privileges, user interaction, and specific runtime conditions; integrity and availability can be affected.

The record

CVE
CVE-2026-16439
Published
Jul 21, 2026
Updated
Jul 21, 2026
Vendor
The Eclipse Foundation
Product
Eclipse OpenJ9
Classifications
CWE-124
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.8.0 <0.60.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Eclipse Foundation · Eclipse OpenJ9version=0.8.0 <0.60.0

Published CVSS scores

5.8Eclipse FoundationCVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:A/VC:N/VI:H/VA:H/SC:N/SI:L/SA:L
9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-124Buffer Underwrite ('Buffer Underflow')

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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