# CVE-2018-7559: OPC UA applications can allow a remote attacker to determine a Server's private key

> Remote attackers can determine a server's private key via an oracle attack using crafted UserIdentityTokens in OPC UA .NET applications.

- **Severity:** Medium 5.3 (`CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 13 Jun 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-gr4c-5rq6-cgh3

## What is CVE-2018-7559?

CVE-2018-7559 is a medium-severity vulnerability in n/a, published on 13 Jun 2018. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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.

Weakness: CWE-320

## Which versions are affected by CVE-2018-7559?

2 open source packages ship an affected version, including OPCFoundation.NetStandard.Opc.Ua. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `OPCFoundation.NetStandard.Opc.Ua` | NuGet | All versions | 1.3.352.12 |
| `OPCFoundation.NetStandard.Opc.Ua` | NuGet | All versions | 1.3.352.12 |

Products: Opcfoundation Ua-.Net-Legacy, Opcfoundation Ua-.Netstandard.

## How do I fix CVE-2018-7559?

Upgrade OPCFoundation.NetStandard.Opc.Ua to 1.3.352.12 or later.

## Is CVE-2018-7559 being exploited?

There is no known exploitation of CVE-2018-7559 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2017-12070](https://insights.sbomify.com/CVE-2017-12070/): Supply chain in n/a (high 8.8)
- [CVE-2018-12585](https://insights.sbomify.com/CVE-2018-12585/): XML external entity in n/a (high 8.2)
- [CVE-2021-27432](https://insights.sbomify.com/CVE-2021-27432/): Denial of service in OPC Foundation OPC UA .NET Standard and OPC UA .NET Legacy (high 7.5)
- [CVE-2018-12087](https://insights.sbomify.com/CVE-2018-12087/): Moderate severity vulnerability that affects OPCFoundation.NetStandard.Opc.Ua (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-7559 and fix it if it is affected.

What it is: CVE-2018-7559 is a medium-severity vulnerability in n/a, published on 13 Jun 2018. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-7559 in the wild and no public exploit code.

Affected packages and fixed versions:
- OPCFoundation.NetStandard.Opc.Ua (NuGet): affected all versions; fixed in 1.3.352.12
- OPCFoundation.NetStandard.Opc.Ua (NuGet): affected all versions; fixed in 1.3.352.12

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2018-7559/ (Markdown: https://insights.sbomify.com/CVE-2018-7559/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-7559
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-7559
- OSV: https://osv.dev/vulnerability/CVE-2018-7559

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-7559/
Summaries are generated and may contain mistakes; the official description above is the record.