# CVE-1999-0894: Missing authorization in n/a

> Local users can write to other terminals due to missing Unix98 pty support in the screen program, allowing unauthorized data modification.

- **Severity:** Critical 10.0 (`AV:N/AC:L/Au:N/C:C/I:C/A:C`)
- **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:** No
- **Published:** 4 Jan 2000
- **Updated:** 1 Aug 2024
- **Also known as:** GHSA-gc92-56cg-2qv2

## What is CVE-1999-0894?

CVE-1999-0894 is a critical missing authorization vulnerability in Redhat Linux, published on 4 Jan 2000. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Red Hat Linux screen program does not use Unix98 ptys, allowing local users to write to other terminals.

## Which versions are affected by CVE-1999-0894?

It affects 1 product.


Products: Redhat Linux.

## How do I fix CVE-1999-0894?

No fix has been published for CVE-1999-0894 yet. Limit exposure of the affected software until one is available.

## Is CVE-1999-0894 being exploited?

There is no known exploitation of CVE-1999-0894 in the wild and no public exploit code.

## Other vulnerabilities in Redhat Linux

- [CVE-2000-1220](https://insights.sbomify.com/CVE-2000-1220/): Privilege escalation in n/a (critical 10.0)
- [CVE-2003-0248](https://insights.sbomify.com/CVE-2003-0248/): Privilege escalation in n/a (critical 10.0)
- [CVE-1999-1542](https://insights.sbomify.com/CVE-1999-1542/): Command injection in n/a (critical 10.0)
- [CVE-1999-1299](https://insights.sbomify.com/CVE-1999-1299/): Privilege escalation in n/a (critical 10.0)
- [CVE-2000-0322](https://insights.sbomify.com/CVE-2000-0322/): Command injection in n/a (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-1999-0894 and fix it if it is affected.

What it is: CVE-1999-0894 is a critical missing authorization vulnerability in Redhat Linux, published on 4 Jan 2000. 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-1999-0894 in the wild and no public exploit code.

Affected product: Redhat 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-1999-0894/ (Markdown: https://insights.sbomify.com/CVE-1999-0894/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-1999-0894
- NVD: https://nvd.nist.gov/vuln/detail/CVE-1999-0894
- OSV: https://osv.dev/vulnerability/CVE-1999-0894

---
From sbomify Insights: https://insights.sbomify.com/CVE-1999-0894/
Summaries are generated and may contain mistakes; the official description above is the record.