CVE-2023-32787: The OPC UA Legacy Java Stack before 6f176f2 enables an attacker to block OPC UA server applications via uncont

Q: How do I fix CVE-2023-32787?

ua java legacy: upgrade to 2023-04-28; ua historian: upgrade to 1.2.0; ua modbus server: upgrade to 1.4.20. Exact commands for each OS are on this page.

Q: Is CVE-2023-32787 being exploited?

CVE-2023-32787 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2023-32787 affect?

CVE-2023-32787 affects ua java legacy, ua historian, ua modbus server. Severity is high (CVSS 7.5). The OPC UA Legacy Java Stack before 6f176f2 enables an attacker to block OPC UA server applications via uncontrolled resource consumption so that they can no longer serve client applications.

Q: How urgent is CVE-2023-32787?

Priority 48/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEUPGRADEUPGRADEUPGRADE

CVE-2023-32787 is a high-severity flaw (CVSS 7.5) affecting ua java legacy, ua historian, ua modbus server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The OPC UA Legacy Java Stack before 6f176f2 enables an attacker to block OPC UA server applications via uncontrolled resource consumption so that they can no longer serve client applications.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 33%)
CISA exploited list	No
Weakness	CWE-400
Published	2023-05-15
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: opcfoundation · prosysopc

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-05-15 15:15 UTCPublished CVE record published
2026-06-17 05:59 UTCUpdated Record last modified

opcfoundation ua java legacy UPGRADE

Affected: < 2023-04-28

Fixed in: 2023-04-28

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy ua-java-legacy || rpm -q ua-java-legacy || ua-java-legacy --version

2. UPGRADE to 2023-04-28 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade ua-java-legacy

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ua-java-legacy

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

prosysopc ua historian UPGRADE

Affected: < 1.2.0

Fixed in: 1.2.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy ua-historian || rpm -q ua-historian || ua-historian --version

2. UPGRADE to 1.2.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade ua-historian

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ua-historian

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

prosysopc ua modbus server UPGRADE

Affected: < 1.4.20

Fixed in: 1.4.20

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy ua-modbus-server || rpm -q ua-modbus-server || ua-modbus-server --version

2. UPGRADE to 1.4.20 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade ua-modbus-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ua-modbus-server

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

prosysopc ua simulation server UPGRADE

Affected: < 5.4.2

Fixed in: 5.4.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy ua-simulation-server || rpm -q ua-simulation-server || ua-simulation-server --version

2. UPGRADE to 5.4.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade ua-simulation-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ua-simulation-server

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2023-32787?

ua java legacy: upgrade to 2023-04-28; ua historian: upgrade to 1.2.0; ua modbus server: upgrade to 1.4.20. Exact commands for each OS are on this page.

Is CVE-2023-32787 being exploited?

CVE-2023-32787 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-2023-32787 affect?

CVE-2023-32787 affects ua java legacy, ua historian, ua modbus server. Severity is high (CVSS 7.5). The OPC UA Legacy Java Stack before 6f176f2 enables an attacker to block OPC UA server applications via uncontrolled resource consumption so that they can no longer serve client applications.

How urgent is CVE-2023-32787?

Priority 48/100. High severity; Remotely exploitable, no login, no user action

Software pages

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References

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