# CVE-2017-20002: Auth bypass in n/a

> Incorrect securetty configuration allows local users to bypass PAM restrictions and escalate privileges to root on systems with blank passwords.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Mar 2021
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2017-20002, GHSA-2m59-rw4g-9g7x

## What is CVE-2017-20002?

CVE-2017-20002 is a high-severity authentication bypass vulnerability in Debian Debian Linux, published on 17 Mar 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The Debian shadow package before 1:4.5-1 for Shadow incorrectly lists pts/0 and pts/1 as physical terminals in /etc/securetty. This allows local users to login as password-less users even if they are connected by non-physical means such as SSH (hence bypassing PAM's nullok_secure configuration). This notably affects environments such as virtual machines automatically generated with a default blank root password, allowing all local users to escalate privileges.

Weakness: CWE-269 (Improper Privilege Management)

## Which versions are affected by CVE-2017-20002?

It affects 2 products.


Products: Debian Debian Linux, Debian Shadow.

## How do I fix CVE-2017-20002?

Upgrade to a fixed version.

## Is CVE-2017-20002 being exploited?

There is no known exploitation of CVE-2017-20002 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-2017-20002 and fix it if it is affected.

What it is: CVE-2017-20002 is a high-severity authentication bypass vulnerability in Debian Debian Linux, published on 17 Mar 2021. 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-2017-20002 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-2017-20002/ (Markdown: https://insights.sbomify.com/CVE-2017-20002/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-20002
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-20002
- OSV: https://osv.dev/vulnerability/CVE-2017-20002

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-20002/
Summaries are generated and may contain mistakes; the official description above is the record.