# CVE-2015-6563: Auth bypass in n/a

> Local attackers can impersonate users and escalate privileges by exploiting improper input validation in the OpenSSH monitor component.

- **Severity:** Medium 6.4 (`CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Aug 2015
- **Updated:** 27 May 2026
- **Also known as:** DEBIAN-CVE-2015-6563, GHSA-2f6c-wrfr-f7rw, UBUNTU-CVE-2015-6563

## What is CVE-2015-6563?

CVE-2015-6563 is a medium-severity authentication bypass vulnerability in Apple Mac Os X, published on 24 Aug 2015. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The monitor component in sshd in OpenSSH before 7.0 on non-OpenBSD platforms accepts extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allows local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the sshd uid to send a crafted MONITOR_REQ_PWNAM request, related to monitor.c and monitor_wrap.c.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2015-6563?

It affects 2 products.


Products: Apple Mac Os X, OpenSSH.

## How do I fix CVE-2015-6563?

Upgrade to a fixed version.

## Is CVE-2015-6563 being exploited?

There is no known exploitation of CVE-2015-6563 in the wild and no public exploit code.

## Other vulnerabilities in Apple Mac Os X

- [CVE-2014-7169](https://insights.sbomify.com/CVE-2014-7169/): GNU Bourne-Again Shell (Bash) Arbitrary Code Execution (critical 9.8, exploited in the wild)
- [CVE-2014-6271](https://insights.sbomify.com/CVE-2014-6271/): GNU Bourne-Again Shell (Bash) Arbitrary Code Execution (critical 9.8, exploited in the wild)
- [CVE-2012-1823](https://insights.sbomify.com/CVE-2012-1823/): PHP-CGI Query String Parameter (critical 9.8, exploited in the wild)
- [CVE-2021-30713](https://insights.sbomify.com/CVE-2021-30713/): Apple macOS Unspecified (high 7.8, exploited in the wild)
- [CVE-2019-8526](https://insights.sbomify.com/CVE-2019-8526/): Apple macOS Use-After-Free (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2015-6563 and fix it if it is affected.

What it is: CVE-2015-6563 is a medium-severity authentication bypass vulnerability in Apple Mac Os X, published on 24 Aug 2015. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2015-6563 in the wild and no public exploit code.

Affected product: Apple Mac Os X. 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-2015-6563/ (Markdown: https://insights.sbomify.com/CVE-2015-6563/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2015-6563
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2015-6563
- OSV: https://osv.dev/vulnerability/CVE-2015-6563

---
From sbomify Insights: https://insights.sbomify.com/CVE-2015-6563/
Summaries are generated and may contain mistakes; the official description above is the record.