# CVE-2016-5008: Auth bypass in n/a

> Remote attackers can bypass VNC authentication by connecting to a libvirt server configured with an empty password, gaining unauthorized access to virtual machine consoles.

- **Severity:** Critical 9.8 (`CVSS:3.0/AV:N/AC:L/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:** 13 Jul 2016
- **Updated:** 6 Aug 2024
- **Also known as:** DEBIAN-CVE-2016-5008, DLA-541-1, DSA-3613-1, GHSA-qmg9-jp26-j65g, MGASA-2016-0248, SUSE-SU-2016:1944-1, SUSE-SU-2016:2053-1, UBUNTU-CVE-2016-5008

## What is CVE-2016-5008?

CVE-2016-5008 is a critical authentication bypass vulnerability in Debian Debian Linux, published on 13 Jul 2016. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

libvirt before 2.0.0 improperly disables password checking when the password on a VNC server is set to an empty string, which allows remote attackers to bypass authentication and establish a VNC session by connecting to the server.

Weakness: CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2016-5008?

It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libvirt` | SUSE:Linux Enterprise Desktop 12 SP1 | All versions | 1.2.18.4-11.7 |
| `libvirt` | SUSE:Linux Enterprise Server 11 SP4 | All versions | 1.2.5-15.3 |
| `perl-Sys-Virt` | SUSE:Linux Enterprise Server 11 SP4 | All versions | 1.2.5-4.2 |
| `libvirt` | SUSE:Linux Enterprise Server 12 SP1 | All versions | 1.2.18.4-11.7 |
| `libvirt` | SUSE:Linux Enterprise Server for SAP Applications 11 SP4 | All versions | 1.2.5-15.3 |
| `perl-Sys-Virt` | SUSE:Linux Enterprise Server for SAP Applications 11 SP4 | All versions | 1.2.5-4.2 |
| `libvirt` | SUSE:Linux Enterprise Server for SAP Applications 12 SP1 | All versions | 1.2.18.4-11.7 |
| `libvirt` | SUSE:Linux Enterprise Software Development Kit 11 SP4 | All versions | 1.2.5-15.3 |
| `libvirt` | SUSE:Linux Enterprise Software Development Kit 12 SP1 | All versions | 1.2.18.4-11.7 |
| `libvirt` | SUSE:Linux Enterprise Workstation Extension 12 SP1 | All versions | 1.2.18.4-11.7 |

Products: Debian Debian Linux, Redhat Libvirt.

## How do I fix CVE-2016-5008?

Upgrade to a fixed version.

## Is CVE-2016-5008 being exploited?

There is no known exploitation of CVE-2016-5008 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-5008 and fix it if it is affected.

What it is: CVE-2016-5008 is a critical authentication bypass vulnerability in Debian Debian Linux, published on 13 Jul 2016. 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-2016-5008 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2016-5008/ (Markdown: https://insights.sbomify.com/CVE-2016-5008/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-5008
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-5008
- OSV: https://osv.dev/vulnerability/CVE-2016-5008

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-5008/
Summaries are generated and may contain mistakes; the official description above is the record.