# CVE-2016-20012: Information disclosure in n/a

> Remote attackers can enumerate valid username and public key combinations on OpenSSH servers by observing challenge responses.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Sep 2021
- **Updated:** 29 May 2026
- **Also known as:** DEBIAN-CVE-2016-20012, GHSA-84j4-ccmw-hwpg, UBUNTU-CVE-2016-20012

## What is CVE-2016-20012?

CVE-2016-20012 is a medium-severity vulnerability in Netapp Clustered Data Ontap, published on 15 Sep 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session. NOTE: the vendor does not recognize user enumeration as a vulnerability for this product

Weakness: CWE-203 (Observable Discrepancy)

## Which versions are affected by CVE-2016-20012?

It affects 5 products.


Products: Netapp Clustered Data Ontap, Netapp Hci Management Node, Netapp Ontap Select Deploy Administration Utility, Netapp Solidfire, OpenSSH.

## How do I fix CVE-2016-20012?

No fix has been published for CVE-2016-20012 yet. Limit exposure of the affected software until one is available.

## Is CVE-2016-20012 being exploited?

There is no known exploitation of CVE-2016-20012 in the wild and no public exploit code.

Public exploit code:

- https://github.com/arturo-b-cmu/cve-2016-20012 (github_poc): https://github.com/arturo-b-cmu/cve-2016-20012

## Other vulnerabilities in Netapp Clustered Data Ontap

- [CVE-2015-7853](https://insights.sbomify.com/CVE-2015-7853/): Integer overflow in n/a (critical 9.8)
- [CVE-2017-9119](https://insights.sbomify.com/CVE-2017-9119/): Denial of service in n/a (critical 9.8)
- [CVE-2016-7480](https://insights.sbomify.com/CVE-2016-7480/): Deserialization in PHP before 7.0.12 (critical 9.8)
- [CVE-2017-5340](https://insights.sbomify.com/CVE-2017-5340/): Integer overflow in n/a (critical 9.8)
- [CVE-2017-11147](https://insights.sbomify.com/CVE-2017-11147/): Information disclosure in n/a (critical 9.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-20012 and fix it if it is affected.

What it is: CVE-2016-20012 is a medium-severity vulnerability in Netapp Clustered Data Ontap, published on 15 Sep 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2016-20012 in the wild and no public exploit code.

Affected product: Netapp Clustered Data Ontap. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2016-20012/ (Markdown: https://insights.sbomify.com/CVE-2016-20012/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-20012
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-20012
- OSV: https://osv.dev/vulnerability/CVE-2016-20012

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-20012/
Summaries are generated and may contain mistakes; the official description above is the record.