# CVE-1999-1129: Missing authorization in n/a

> Remote attackers can inject frames into other VLANs by forging trunking tags, bypassing network segmentation on Cisco Catalyst switches.

- **Severity:** High 7.5 (`AV:N/AC:L/Au:N/C:P/I:P/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:** 12 Sep 2001
- **Updated:** 1 Aug 2024
- **Also known as:** GHSA-29q9-4h2h-9p7g

## What is CVE-1999-1129?

CVE-1999-1129 is a high-severity missing authorization vulnerability in Cisco Ios, published on 12 Sep 2001. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Cisco Catalyst 2900 Virtual LAN (VLAN) switches allow remote attackers to inject 802.1q frames into another VLAN by forging the VLAN identifier in the trunking tag.

## Which versions are affected by CVE-1999-1129?

It affects 2 products.


Products: Cisco Catalyst 2900 Vlan, Cisco Ios.

## How do I fix CVE-1999-1129?

No fix has been published for CVE-1999-1129 yet. Limit exposure of the affected software until one is available.

## Is CVE-1999-1129 being exploited?

There is no known exploitation of CVE-1999-1129 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-1999-1129 and fix it if it is affected.

What it is: CVE-1999-1129 is a high-severity missing authorization vulnerability in Cisco Ios, published on 12 Sep 2001. 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-1999-1129 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-1999-1129/ (Markdown: https://insights.sbomify.com/CVE-1999-1129/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-1999-1129
- NVD: https://nvd.nist.gov/vuln/detail/CVE-1999-1129
- OSV: https://osv.dev/vulnerability/CVE-1999-1129

---
From sbomify Insights: https://insights.sbomify.com/CVE-1999-1129/
Summaries are generated and may contain mistakes; the official description above is the record.