# CVE-1999-0398: Auth bypass in n/a

> SSH server allows login for users with expired accounts, bypassing account expiration controls.

- **Severity:** Medium 4.6 (`AV:L/AC:L/Au:N/C:P/I:P/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Feb 2000
- **Updated:** 1 Aug 2024
- **Also known as:** GHSA-4q8w-3rhr-5qw7

## What is CVE-1999-0398?

CVE-1999-0398 is a medium-severity authentication bypass vulnerability in n/a, published on 4 Feb 2000. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

In some instances of SSH 1.2.27 and 2.0.11 on Linux systems, SSH will allow users with expired accounts to login.

## Which versions are affected by CVE-1999-0398?

It affects 2 products.


Products: Ssh Ssh, Ssh Ssh2.

## How do I fix CVE-1999-0398?

No fix has been published for CVE-1999-0398 yet. Limit exposure of the affected software until one is available.

## Is CVE-1999-0398 being exploited?

There is no known exploitation of CVE-1999-0398 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-1999-0248](https://insights.sbomify.com/CVE-1999-0248/): Race condition in n/a (critical 10.0)
- [CVE-1999-0013](https://insights.sbomify.com/CVE-1999-0013/): Information disclosure in n/a (high 8.4)
- [CVE-2001-1473](https://insights.sbomify.com/CVE-2001-1473/): Weak cryptography in n/a (high 7.5)
- [CVE-2001-1475](https://insights.sbomify.com/CVE-2001-1475/): SSH before 2.0, when using RC4 and password authentication, allows remote attackers to replay messages until a new server key (VK) is generated. (high 7.5)
- [CVE-2001-1476](https://insights.sbomify.com/CVE-2001-1476/): SSH before 2.0, with RC4 encryption and the "disallow NULL passwords" option enabled, makes it easier for remote attackers to guess portions (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-1999-0398 and fix it if it is affected.

What it is: CVE-1999-0398 is a medium-severity authentication bypass vulnerability in n/a, published on 4 Feb 2000. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-1999-0398 in the wild and no public exploit code.

Affected product: n/a. 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-1999-0398/ (Markdown: https://insights.sbomify.com/CVE-1999-0398/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-1999-0398
- NVD: https://nvd.nist.gov/vuln/detail/CVE-1999-0398
- OSV: https://osv.dev/vulnerability/CVE-1999-0398

---
From sbomify Insights: https://insights.sbomify.com/CVE-1999-0398/
Summaries are generated and may contain mistakes; the official description above is the record.