CVE-2018-7559

OPC UA applications can allow a remote attacker to determine a Server's private key

5.3 MediumFix available

An issue was discovered in OPC UA .NET Standard Stack and Sample Code before GitHub commit 2018-04-12, and OPC UA .NET Legacy Stack and Sample Code before GitHub commit 2018-03-13. A vulnerability in OPC UA applications can allow a remote attacker to determine a Server's private key by sending carefully constructed bad UserIdentityTokens as part of an oracle attack.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: High
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: None
Availability: None

Exploit likelihood

1.15%Down 0.2 points since Apr 14, 2021

What each source reports

NVD Score used 5.3

Record: CVE-2018-7559
CVSS 3.0: 5.3 MediumCVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS 2.0: 3.5 LowAV:N/AC:M/Au:S/C:P/I:N/A:N
Weakness: CWE-320
Updated: 2026-11-02

CVE List No score

Record: CVE-2018-7559
Updated: 2026-11-02

EUVDEUVD-2018-0604 No score

Record: EUVD-2018-0604
Updated: 2026-11-03

GitHub AdvisoriesGHSA-gr4c-5rq6-cgh3 5.3

OPC UA applications can allow a remote attacker to determine a Server's private key

Record: GHSA-gr4c-5rq6-cgh3
CVSS 3.0: 5.3 MediumCVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Updated: 2026-11-02

OSV 5.3

Record: CVE-2018-7559
CVSS 3.0: 5.3 MediumCVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Updated: 2026-11-02

OSVGHSA-gr4c-5rq6-cgh3 5.3

OPC UA applications can allow a remote attacker to determine a Server's private key

Record: GHSA-gr4c-5rq6-cgh3
CVSS 3.0: 5.3 MediumCVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`OPCFoundation.NetStandard.Opc.Ua` NuGet	through 1.3.352.11	1.3.352.12
`OPCFoundation.NetStandard.Opc.Ua` NuGet	before 1.3.352.12, plus listed versions 0.4.00.4.10.4.30.4.40.4.5 Show 12 moreShow less 1.3.3481.3.3491.3.3501.3.350.11.3.350.31.3.350.41.3.350.51.3.350.61.3.351.71.3.352.101.3.352.111.3.352.9	1.3.352.12

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2018-7559 is a medium vulnerability (CVSS 5.3) in Opcfoundation Ua-.net-legacy, published June 13, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.15%, the 67th percentile. Fixed in OPCFoundation.NetStandard.Opc.Ua 1.3.352.12.