# CVE-2000-0268: Denial of service in n/a

> Remote attackers can cause a denial of service and system reboot on Cisco IOS devices by sending a malformed Telnet option.

- **Severity:** Medium 5.0 (`AV:N/AC:L/Au:N/C:N/I:N/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Jun 2000
- **Updated:** 8 Aug 2024
- **Also known as:** GHSA-c43m-vj32-q46r

## What is CVE-2000-0268?

CVE-2000-0268 is a medium-severity denial of service vulnerability in Cisco Ios, published on 2 Jun 2000. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Cisco IOS 11.x and 12.x allows remote attackers to cause a denial of service by sending the ENVIRON option to the Telnet daemon before it is ready to accept it, which causes the system to reboot.

## Which versions are affected by CVE-2000-0268?

It affects 12 products.


Products: Cisco 3660 Router, Cisco 7100 Router, Cisco 7200 Router, Cisco 7500 Router, Cisco Accesspath, Cisco As5200, Cisco As5300, Cisco As5800, Cisco Ios, Cisco System Controller 3640, Cisco Ubr7200, Cisco Voice Gateway As5800.

## How do I fix CVE-2000-0268?

No fix has been published for CVE-2000-0268 yet. Limit exposure of the affected software until one is available.

## Is CVE-2000-0268 being exploited?

There is no known exploitation of CVE-2000-0268 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2000-0268 and fix it if it is affected.

What it is: CVE-2000-0268 is a medium-severity denial of service vulnerability in Cisco Ios, published on 2 Jun 2000. 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-2000-0268 in the wild and no public exploit code.

Affected product: Cisco Ios. 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-2000-0268/ (Markdown: https://insights.sbomify.com/CVE-2000-0268/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2000-0268
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2000-0268
- OSV: https://osv.dev/vulnerability/CVE-2000-0268

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From sbomify Insights: https://insights.sbomify.com/CVE-2000-0268/
Summaries are generated and may contain mistakes; the official description above is the record.