# CVE-2015-5600: Denial of service in n/a

> Remote attackers can cause CPU exhaustion and facilitate brute-force attacks by sending a duplicative keyboard-interactive device list to OpenSSH.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Aug 2015
- **Updated:** 27 May 2026
- **Also known as:** DEBIAN-CVE-2015-5600, GHSA-6x25-gfx2-5crp, MGASA-2015-0295, UBUNTU-CVE-2015-5600

## What is CVE-2015-5600?

CVE-2015-5600 is a high-severity denial of service vulnerability in OpenSSH, published on 3 Aug 2015. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The kbdint_next_device function in auth2-chall.c in sshd in OpenSSH through 6.9 does not properly restrict the processing of keyboard-interactive devices within a single connection, which makes it easier for remote attackers to conduct brute-force attacks or cause a denial of service (CPU consumption) via a long and duplicative list in the ssh -oKbdInteractiveDevices option, as demonstrated by a modified client that provides a different password for each pam element on this list.

Weakness: CWE-264, CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2015-5600?

It affects 1 product.


Products: OpenSSH.

## How do I fix CVE-2015-5600?

Upgrade to a fixed version.

## Is CVE-2015-5600 being exploited?

There is no known exploitation of CVE-2015-5600 in the wild and no public exploit code.

Public exploit code:

- Professional cybersecurity assessment demonstrating vulnerability identification, CVSS severity scoring, MITRE ATT&CK framework application, and detailed remediation planning for OpenSSH 6.6.1p1 critical vulnerabilities (CVE-2016-0777, CVE-2015-5600) (github_poc): https://github.com/Abdirisaq-ali-aynab/vulnerability-assessment

## Other vulnerabilities in OpenSSH

- [CVE-2003-0786](https://insights.sbomify.com/CVE-2003-0786/): Auth bypass in n/a (critical 10.0)
- [CVE-2003-0693](https://insights.sbomify.com/CVE-2003-0693/): Memory corruption in n/a (critical 10.0)
- [CVE-2002-0640](https://insights.sbomify.com/CVE-2002-0640/): Memory corruption in n/a (critical 10.0)
- [CVE-2001-0144](https://insights.sbomify.com/CVE-2001-0144/): Integer overflow in n/a (critical 10.0)
- [CVE-2000-0999](https://insights.sbomify.com/CVE-2000-0999/): Memory corruption in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2015-5600 and fix it if it is affected.

What it is: CVE-2015-5600 is a high-severity denial of service vulnerability in OpenSSH, published on 3 Aug 2015. 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-2015-5600 in the wild and no public exploit code.

Affected product: OpenSSH. 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-2015-5600/ (Markdown: https://insights.sbomify.com/CVE-2015-5600/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2015-5600
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2015-5600
- OSV: https://osv.dev/vulnerability/CVE-2015-5600

---
From sbomify Insights: https://insights.sbomify.com/CVE-2015-5600/
Summaries are generated and may contain mistakes; the official description above is the record.